Wiring Harness & Modern Fuse/Relay Block

[amcordo]

Hi!

So I just ordered all the wiring, labels, and heat shrink I need to make my wiring harness with a modern fuse/relay block (picking up the block off an 2000 something chrysler sedan at the junkyard tomorrow morning for $5).

My only thing I don't have are connectors for the wires. Has anyone else made their own wire harness and struggled with what type of connectors to use? The smart move are probably weather lock connectors (the type used on GM cars I think), but they're extremely expensive. I'm talking like $100 just to do up my dash, future roofrack wiring, and inside the engine compartment the way I want it done. What else is out there that anyone has used (aside from the quick disconnect metal spades you can pick up at any old supermarket)?

[thixon]

You can use marine grade connectors with the heat shrink ends. http://www.jamestowndistributors.com/userportal/show_product.do?pid=706&familyName=Ancor+Adhesive+Lined+Heat+Shrink+AWG+Bu tt+Connectors

Plenty of places carry them. If you choose to use the butt connectors to link everything up, just remember to leave a little slack in case you ever have to take things apart again. Its not the best solution, but it is a cheap, mostly weatherproof option.

[gudjeon]

I used those cheap 4/5 wire flat trailer connectors. If I have to, I can unplug and remove all the body without cutting a thing. Plenty of dielectric grease and no problems after 5 years. :thumb-up:

[chefplw]

check out www.delcity.net (http://www.delcity.net) all kinds of wiring supplies

[amcordo]

check out www.delcity.net (http://www.delcity.net) all kinds of wiring supplies


The quick connectors http://www.delcity.net/store/Quick-Connectors/p_9108.a_1 are EXACTLY what I'm looking for. Thank you!!! They're reasonably priced and will allow me to make the whole car modular - so I can take it apart without cutting wires.

Nice and inexpensive too...

[alaskajosh]

Sounds like you found what you were after there but I might make another suggestion for any one else considering building a harness. Terminal strips make for reasonably quick disconnects and offer added modularity, adaptability, ability to easily add or change things down the road. Easy field repairs, troubleshooting. And Series Rover'esque simplicity.

This is the only picture I have of my harness build, taken an hour into it... after that I got swept up in the fun and forgot to take any more shots
http://i459.photobucket.com/albums/qq318/jhofoshomofo/other%20LR/IMG_3885.jpg

[TeriAnn]

So I just ordered all the wiring, labels, and heat shrink I need to make my wiring harness with a modern fuse/relay block (picking up the block off an 2000 something chrysler sedan at the junkyard tomorrow morning for $5).

I've scratch built 6 wiring harnesses for Land Rovers so far. My first one was for my own truck about 30 years ago and that one was a stock harness except for a Ford alternator with remote regulator. I ripped it out a couple years ago when I switched to EFI, a big fuse block and a bunch of relays. I've done two trucks that subsequentially took a year drive around the world without any electrical issues and just finished off the last rewire about a month ago.

Personally I dislike wire labels. To my eyes they look strange and I wouldn't count on them staying there and legible forever. I'm a strong believer in using British standard striped and solid colour wire. A glance of any wire anyplace in the truck tells me exactly what that wire is for and where it goes. I don't need to look for a label at the end of a wire that has a scrapped off insulation and guess it it the same wire as the label.

For fuse blocks I look to Marine grade hardware and yes for my last job I attached a terminal block to the bulkhead behind the main instrument panel. It does make things go faster and leaves a neater harness. I tend to put an insulated tie point on the right inside wing panel right behind the battery and headlamp, electric fan and horn relays go next to them with a single fuse for the relays. I run the alternator out wire to the tie post then to the starter button. And the relays go to the tie point for power via a fuse.

There is a marine fuse holder that has a hole for a mounting bolt hole and has triple water seals between the two parts.

For relays, I have been using relys from mid-90's Cadillac El Dorados. There is a group of 3 on the front left inner wheel well that have their own mounting bracket. One bolt gets all three relays and the mounting bracket.
These Bosh relays are potted where the leads come out and have triple water seals between the parts. They are about as water proof as you can get




My only thing I don't have are connectors for the wires. Has anyone else made their own wire harness and struggled with what type of connectors to use?

I used to solder on Lucas bullet connectors as was used by the factory. But it doubles the time to build a harness. My last two jobs, the EFI conversion to my truck and a friends 88, were done with hardware store insulated connectors. Ring connectors and double insulated spade connectors with dielectric grease slathered on spade connections in the engine bay and under the truck. Much faster, seems to work as well as fresh bullet connectors and any rewiring can be quickly done in the field with local hardware store parts.

Good luck on your project

[amcordo]

Thanks everyone for the tips and pics!

I want to stay away from bullet connections because they're not very good conductors - a bullet connectors only touch each other in a very small area. The spade connectors are better because the flat surfaces touch each other across a larger area and conduct more electricity. I know this from previous work in the audio world where banana connectors were being phased out for the exact same reason.

[alaskajosh]

Personally I dislike wire labels. To my eyes they look strange and I wouldn't count on them staying there and legible forever.

Printed labels inserted under clear heat shrink are well protected and should be legible for a very long time.

My harness was as much custom as it was stock Land Rover so the color codes would have soon been meaningless. I broke the colors down as far as White=switched power, Red=unswitched, Green=intrument related, Black=ground. Labels let me be specific as well (ie: RLoHL, RHiHL). Printed on either end there are no problems that can't be quickly sorted with a test light. The highest quality wire I could find came only in basic colors and no tracers... mediocre quality untinned wire and stiff plasticy insulation is disgusting stuff.

I broke the wiring diagram into systems (lighting, engine/ignition, instruments, etc), printed those onto 3x5 cards, laminated, and stored in the Pelican case that houses the fuse block.

Kind regards, Josh

[KingSlug]

I know this might be over the top, but why not use metri-pack connectors. I have had good success getting them at Chevy/GM dealers.

http://www.metripack.com/

For some really cool products checkout Cooper/Bussman catalog pg 6/7 for fuse/relay box.

http://www.cooperbussmann.com/pdf/fdee239d-3e78-4df3-832f-fea4236a26bf.pdf

Jared

[109 Pretender]

For anyone who wants to get the original style connectors and wiring w/correct color codes check out Rhode Island wiring. I remember seeing them in Hemimngs way, way back when I was a little kid and they are very reasonable on pricing - I think I paid about 10.00 for 100 of the OEM clear rubberized covers for the spade connectors. They have the Lucas bullets as well if you want to stay stock. But, as others have mentioned, there are better solutions out there...

Release the dark prince - let some smoke out of those wires by using American blade fuses - just kidding! :nono: You should always use British fast blow fuses (Lucas) w/British wiring harnesses

good luck with those wires!

[amcordo]

For anyone who wants to get the original style connectors and wiring w/correct color codes check out Rhode Island wiring. I remember seeing them in Hemimngs way, way back when I was a little kid and they are very reasonable on pricing - I think I paid about 10.00 for 100 of the OEM clear rubberized covers for the spade connectors. They have the Lucas bullets as well if you want to stay stock. But, as others have mentioned, there are better solutions out there...

Release the dark prince - let some smoke out of those wires by using American blade fuses - just kidding! :nono: You should always use British fast blow fuses (Lucas) w/British wiring harnesses

good luck with those wires!

You can get ATO / ATC (blade type) fuses that are fast blowing or slow to blow. :thumb-up: Good time as any for a lesson for everyone who might not be as electronically inclined:

Use fast blow fuses almost exclusively. Fast blow refers to how long it takes the fuse to open a circuit once it is overloaded. Fast blow fuses will open a circuit almost immediately during an overload (like a short).

The only time you should use a slow blow fuse is on a piece of equipment that has a large in-rush current. If you've an electric fan, you'll want a slow blow fuse on that. The fan uses more energy during startup than it does while running; the slow blow fuse may be overloaded for a second when the fan starts up, but well below its rated peak while the fan is at speed. The slow blow fuse will allow for the in-rush overload, but if a dangerous condition occurs it'll still blow within a second or two. The downside to this: if there is a short that's happening only periodically (for instance: a bare wire that is loose and only occasionally brushes the frame) the fuse may not be triggered. THAT is why you want to use slow-blow fuses as sparingly as possible.

[printjunky]

I just pulled a fuse/relay box off a mid-90's Caddy, that should fit great on my firewall. How did you guys tap into your modern fuse box? Was it reversible? Anything original left? Most of the wires on the new fuse box, I left long enough to splice into, but I'd really like to replace the actual connector to the fuse sockets and run entirely new wires with no splices. And of course the wires only run to one side of the box, a power rail is on the other. Which is fine, but I'm trying to design a reversible system, so that feels like it's making it more complicated. I guess I can just disconnect anything that goes into the Lucas fuse box, and take that power from that rail on the fuse box ...

Also, this box has a 145A main fuse between the battery and the alternator. Keep it? Change the rating? Get rid of it? Any suggestions. Unlikely to be any harm, and help protect my main wires from frying, I guess.

And I need to divvy (and combine a couple of) up my circuits. Any thoughts?

Oh, and (still just thinking out loud here), I need to figure out how I'm going to get my switched circuits routed. I guess send power to the switch (40A?) and then send power out to those individual fuses .... time to get out some paper and start diagramming. I'll post pics of the new box after work.

[amcordo]

I just pulled a fuse/relay box off a mid-90's Caddy, that should fit great on my firewall. How did you guys tap into your modern fuse box? Was it reversible? Anything original left? Most of the wires on the new fuse box, I left long enough to splice into, but I'd really like to replace the actual connector to the fuse sockets and run entirely new wires with no splices. And of course the wires only run to one side of the box, a power rail is on the other. Which is fine, but I'm trying to design a reversible system, so that feels like it's making it more complicated. I guess I can just disconnect anything that goes into the Lucas fuse box, and take that power from that rail on the fuse box ...

Also, this box has a 145A main fuse between the battery and the alternator. Keep it? Change the rating? Get rid of it? Any suggestions. Unlikely to be any harm, and help protect my main wires from frying, I guess.

And I need to divvy (and combine a couple of) up my circuits. Any thoughts?

Oh, and (still just thinking out loud here), I need to figure out how I'm going to get my switched circuits routed. I guess send power to the switch (40A?) and then send power out to those individual fuses .... time to get out some paper and start diagramming. I'll post pics of the new box after work.


Don't remove the original wires & connectors!!!

i did, and had to hunt to find the female connectors to sit in the slots where the originals set, and they move and they don't fit perfect, bla bla bla. Just do very firm splices with an iron and you'll be better off.

I'm in the process of redoing the fuse box right now to make up for those mistakes.

[greenmeanie]

Oh, and (still just thinking out loud here), I need to figure out how I'm going to get my switched circuits routed. I guess send power to the switch (40A?) and then send power out to those individual fuses .... time to get out some paper and start diagramming. I'll post pics of the new box after work.

This is on location you can make a significant upgrade to the electric system. Use the switched power from the ignition switch as the low power trigger for your switched 12V relay. It takes all that load away from the switch which will now last longer and removes some of the high amp loads from the harness behind the dash.

And as to the free advice for the 'BEST' method of making joints -both solder and crimp have their place but providing strain relief to the joint is the most important factor to its longevity. As to which you should use, try practicing both methods and find out which you are best at. Dealing with aircraft power systems I can say that very few people who don't hold rating tickets can do a truly good solder joint.

[bkreutz]

I think a 145A fuse between the alternator and the fuse block is like not having a fuse at all. You want to rate that fuse a bit higher than the output potential of the alternator/generator you have. So unless you have a fire truck alternator adapted to your engine(:D) it needs a smaller fuse (one with less capacity, not physically smaller:))

[mongoswede]

I think a 145A fuse between the alternator and the fuse block is like not having a fuse at all. You want to rate that fuse a bit higher than the output potential of the alternator/generator you have. So unless you have a fire truck alternator adapted to your engine(:D) it needs a smaller fuse (one with less capacity, not physically smaller:))

I think the aluminum in your rover will catch on fire before a 145A fuse will blow :D

[printjunky]

Yeah, 145A is crazy. It's the highest main fuse I've seen on a regular pass. car. And this Caddy probably had a 100A alt, max, I'd guess. Not sure I understand how it fits into the design ... anyway, it's probably a little overkill to even have it in the Rover, if I'm going to fuse everything else, but I can easily downrrate it.



Greenmeanie, I never went for my A&P, but I spent a few years working on jets in the Air Force. And then a bunch of years as a stagehand (soldering mic cables, and such). So while I may forget to slide the shrink wrap on before making the joint, and very occasionally immediately forget the second time (by very occasionally, I of course, mean earlier this week), I've put some irons to the wire.

[printjunky]

I was wrong. The main fuse in that box is 175A!

Tony, you OK with me documenting my upgrade here under this appropriately title thread you started, or want me to start another? Your thread, your choice.

[amcordo]

I was wrong. The main fuse in that box is 175A!

Tony, you OK with me documenting my upgrade here under this appropriately title thread you started, or want me to start another? Your thread, your choice.


BAHAHA I definately lost the right to tell people not to hijack my threads...

Perfect place to post the ways you're doing it! More learning for everyone.

[kevkon]

And as to the free advice for the 'BEST' method of making joints -both solder and crimp have their place but providing strain relief to the joint is the most important factor to its longevity. As to which you should use, try practicing both methods and find out which you are best at. Dealing with aircraft power systems I can say that very few people who don't hold rating tickets can do a truly good solder joint.

I agree, but most of the problems I have encountered with auto wiring have been related to bad crimp connections. Proper crimping is a skill and requires the proper components. Too often people use the incorrect connector or crimp the connector incorrectly. The worse thing about this is that it is usually responsible for the dreaded intermittent electrical issues.
I think that a person who is willing to solder is a person willing to spend more time and is probably more likely to be careful.
For anyone not comfortable with soldering or crimping, consider using the Posi-Lock and Posi-Seal connectors.

[jac04]

..consider using the Posi-Lock and Posi-Seal connectors.
I used the Posi-Seal connectors for the rear lights on my Lightweight. They work well, but are expensive.

[mongoswede]

I agree, but most of the problems I have encountered with auto wiring have been related to bad crimp connections. Proper crimping is a skill and requires the proper components. Too often people use the incorrect connector or crimp the connector incorrectly. The worse thing about this is that it is usually responsible for the dreaded intermittent electrical issues.
I think that a person who is willing to solder is a person willing to spend more time and is probably more likely to be careful.
For anyone not comfortable with soldering or crimping, consider using the Posi-Lock and Posi-Seal connectors.

A good crimp connection with a proper heat shrink seal will work just as well as a good solder connection. In some applications the solder connections are not advisable because vibration can fatigue the solder and cause it to fail. You want to spend the money on the good crimp tool and the good crimp connectors when possible. The kind the rolls both sides of the crimp inwards as opposed to the kind that just flattens the barrel.

[kevkon]

You can also have the best of both worlds by using a Crimp Solder Seal Heat Shrink connector. You crimp it and heat it which melts the connector and the shrink casing. Tht provides a sealed connection with strain relief. One thing though, be careful not to mix these up with the shrink- crimp only connectors which look similar but don't have a fusible ferrule that melts.

[printjunky]

OK, here's the fusebox I found, that I think will work. Obviously I'll replace those 40s with whatever's appropriate. I want to fuse everything, and any future adds, so my target was 20 circuits. This has 22 or so (the blank spots have no fuse sockets)

I guess I have to decide how to integrate the switched/unswitched circuits, as this box just has the main power in on one rail, through the fuses, and out to whatever, so it can't be both as far as I can tell.

Maybe I'll keep one side on the Lucas box ... So what's not switched?

- Headlights
- Flashers
-

Hmmm, can't think of (or see on the schematic) anything else. Any other candidates?

And there's no reason I couldn't put the headlights on the switched side, and I keep the flashers on their own unswitched circuit right?

[printjunky]

Oh, and the horn.

(and the inspection sockets which were always going to be switched and getting fused, of course (plus I'll be adding 2 modern power outlets to the emergency flasher center dash thingy))

[printjunky]

OK, here's the fuse box diagram, all mapped out and double checked.

I haven't really assessed it too much to see what kind of design might be best, except to note some possible relay usage for my headlights. (remembering I have 4 headlights - ie: left hi beams 60w/13.4v = 4.5Ax2 = 9A, etc).

I was thinking of ganging all 4 hi beams (18A), and all 4 low beams (16.4A) on just two relays, but I figure the more redundancy, the less likely I'll lose entire systems or sub-systems).

I also have to figure out how those other sockets fit in. I'm guessing those are also relays. I'll look up the part number (Bosch units) when I get home.

My wire length to the dash is about 36 inches, so hopefully I can design the rest and start soldering in extension wires tonight. Maybe mount the bracket on the firewall, too if I can beat prime mosquito time.

[JackIIA]

Nice looking diagram. What did you use to create that.

[printjunky]

Thanks. I should have opened it up a bit more, left myself more room to label. I used Adobe Illustrator CS2. Any moderately advanced vector graphic program can do the same. One of my interns uses a similar open source (read: free) program called Inkscape. I just installed it this week at home to see how it compares.

[printjunky]

So it took pretty much all day to figure out how I was going to mount the box to the firewall. I ended up having to modify the fuse box bracket, and I'll have to do a little rerouting of the heater hoses. They were a problem, because I have an aux heater that taps off of the heater hoses near the spot I want to put the box. Pics show my aux heater hoses going into the cabin, and the "H" that tees off to the aux hoses.

I didn't get a before picture of the bracket, but made a quick drawing of what I modified. The drawing is looking at the end of the bracket/fuse box.

[printjunky]

The fuse box bracket on the firewall.

[printjunky]

Can anyone confirm for me: On the starter solenoid, there's a tab that stays hot with the key in an on position, correct?

I have too much torn apart to easily check at the moment. Looks that on the diagram of the solenoid in my Haynes.

[printjunky]

OK, I figured out a little more. Looks like I was not correct. The starter relay is just an intermittent relay. Though the RN diagram differs with the Haynes as far as that part of the wiring goes, so there's still some confusion)

The thing I'm trying to solve is getting switched power safely to my add-on fuse box.

Obviously, I could probably just do something like 8 or 6 gauge wire from battery to starter switch (#1), fused (80A?) near the battery. Then take a similar wire back out (from #4?) to my fuse box (probably for extra safety also fused there with the maxi fuse that already exists (smallest rating = 100A).

Even better , and safer/more reliable though, I could get a continuous duty 100A relay, with just the switching wire from the ignition switch to the relay. This would eliminate any significant wire (and current) from battery to ignition switch, keeping most high current power under the hood.

I'd still have to take some power to the ignition switch for the switching current for the relays, but that's pretty small current, and some power to the opriginal fuse box, where I'll be leaving the non-switched circuits (horn, emergency flasher, what else?)

Anyone concur? Have other opinions?