Rewiring problems...

[superstator]

I'm almost done putting in my new wiring harness, and for the most part it's gone amazingly smoothly. I've hit two snags though: first is the brake switch.

The brake switch worked fine before I cut out the old harness, but no luck after. I appear to have a dual circuit setup from a santana, like this: http://www.heystee-automotive.com/pa...brks/servo.htm. The switch itself looks a little like a small spark plug or glow plug, with two spade connectors on one end and a button on the other, where it goes into the pedal housing to be actuated by a little plate. I tried putting a multimeter on it to check for continuity between the spades when the button is pushed, nothing. So either I'm completely misunderstanding how it works, or I broke it somehow disconnecting the old wires. Hints on either what I'm doing wrong, or where to find a new one?

Second snag is the wiper motor (very important here in Oregon). I had trouble with it when I first got the truck, and then it magically started working again. Now it's defying me again. I've got a decent ground to the ground spade, and a single wire bringing 12v from the switch to terminals 1 and 2. When I switch it on, nothing happens whatsoever. Am I right in assuming both those terminals are positive, or should I have one of them wired to another ground? If so, does it matter which?

Other than that, it's made a huge improvement. Truck actually sat for a full 5 days last week with the battery connected, without discharging at all. Amazing!

[CliftonRover]

if you cannot get the brake lights to go on by jumping the switch circuit then check your rear grounds. otherwise get a new switch they are cheap, also make sure it is adjusted correctly and being engaged.

[superstator]

Yes, but which switch?

[jp-]

On those brake switches, some of them are NO (normally open) and some are NC. Did you try connecting the switch and seeing if the brake lights came on? And if that fails, check to see if they come on with the button pressed. (In short, check continuity of the switch both with the button pressed and with it not.)

Is the wiper motor the single large one that mounts in the left corner of the dash, and runs the wipers with a push-pull cable? It has been a while since I wired mine up and it is only a single speed. Yours sounds like it might be a two-speed (from a SIII Rover). If that's the case, you'll need to check your latter wiring diagrams on that. Also, make sure the cable is not binding.

[superstator]

I can't measure any continuity through the switch in either state. I've assumed it was NO, and wired the new harness as such - and yes, jumping the wires around the switch does light up the stop lamps fine. Here's a glamour shot of the switch:

Is the wiper motor the single large one that mounts in the left corner of the dash, and runs the wipers with a push-pull cable?

It's not a push pull, it's a, err, worm drive with a flexible drive shaft? Not sure the right thing to call it; like the flexible drive line on a post-hole digger. I think anyway, I haven't had it apart any further than I needed to look at the electrical connections . It's a 67 NADA 109 like yours, but I don't know if the motor may have been replaced at some point with a different unit...

[CliftonRover]

I use west marine wipers so I can't help you there, but that switch can be problematic, rover uses that switch for brake and reverse engaugement now. I just ordered one the other day, if you replace it you should be fine. sorry if this is not helpful..

[thixon]

Cliftonrover,

Which wipers from WM are you using?

[CliftonRover]

just the standard one speed model. they are 60 bucks or so but they are all stainless steel and are simple and they always work. you will need to get different wiper blades though the boat wiper blades are lame.

[junkyddog11]

just the standard one speed model. they are 60 bucks or so but they are all stainless steel and are simple and they always work. you will need to get different wiper blades though the boat wiper blades are lame.

The individual style wiper motors are Marinco AFI. My GF sells them at her Marine hdwr store.

http://www.marinco.com/productline/wiper-motors

[CliftonRover]

yeah those are them

[Mercedesrover]

I hate those switches. They're a pain to get adjusted right if you can get them adjusted at all. Throw it in the trash and splice in a standard in-line switch.

[mechman]

Ahh yes, those buggers! Typical Mil-spec brake light switch, common on Series III 109's. They're really not too hard to adjust, if you hang a mirror behind your truck so you can see your brake light (or hook a continuity tester to your contacts if you're not that adventurous).

That switch should be open (button depressed) when the pedal is at rest (up). When you hit the pedal, the button pops out, the contact is made and your lights (should) go on. If you're not getting any continuity with the button out, then the contacts inside are probably corroded and your switch should be replaced. OR it shorted and your hot lead is now dead. Either way, a new one is called for.

To adjust the bugger, run the lock nut up the shaft, then gently screw it into the hole until it bottoms out. Hook up the wires, and back it out slowly until your brake lights go on (make sure you have power to the switch first! It should have an unswitched full-time hot anyway...), then turn it back in until the lights go off, then another tiny smidge more. Test it a few times by hitting your brake pedal (that's why a mirror is preferred) and tweak as necessary. Unplug the switch and straighten out your wires, carefully tighten your lock nut and plug it back in.

Voila!

Mech

[Rineheitzgabot]

About 3 years ago, I wired a small micro-switch right to the dash that actuates with the movement of the brake pedal.

I went through the adjustment nightmare of that OEM switch. I call it a nightmare because there's nothing like discovering that your brake lights don't work, after you saw them work twenty times pressing the brake pedal in the garage; 5 days later to discover that they don't work again. At least that's how it went for me. I would adjust the switch, and it would work fine. Over time however, it would come out of adjustment.

I am sure there's a "sweet spot". But I am not going to spend the rest of my life trying to find it. I by-passed it. Now they work consistently (I still check them before almost every trip).

[mechman]

I've found that usually the problem isn't with the adjustment, it's that either the contacts inside the switch have some corrosion on them or that the button doesn't pop back out all the way when you hit the pedal. When you disturb the switch, the button resets and your lights work again for a while. Or, of your lights stay on, often the problem is that your pedal isn't coming back up fully, and you have an issue in your master cylinder.

A little dab of dielectric grease on the button sometimes helps on a new switch.

Of course, YMMV.

Mech

[superstator]

So, I guess I'm confused - I thought pressing the brake pedal pressed the button in? I had a friend pump the brake while I peered into the opening for the switch, and I swore I saw the plate in there moving towards the opening as he pressed the pedal. Are there versions that work that way, or was I halucinating again?