Brakes light up Park and Side lights, too

[HinFL]

When I press the brake pedal the Stop lights illuminate, as they should, but so do the 2 front Park lights and all 4 Side lights. Can those of you more knowledgeable than I (that should include just about everybody on this forum) give me some advice about where to start looking for the culprit?

I'm guessing it's a short or bad ground somewhere. I have a good working relationship with the wiring diagram, but have difficulties applying its theoretical layout to actual locations on the vehicle; specifically where runs of wiring are and where items are grounded. In reply(s) to this inquiry, please assume very little mechanical prowess and you'll probably be close to the mark. I have di-electric grease and the ability to follow rudimentary instructions, though...

It has finally cooled off a little in our neck of the woods and I'm happy to report that "Aggie" the Rover is returning to her Daily Driver status. She's a 1973 Series III 88" NAS, by the way. Thanks in advance for any assistance you can offer.

[LaneRover]

I would also assume a bad ground. The rear lights ground against the frame in the back. If your truck is left hand drive the ground should be on the passenger side behind the rear tire.

In the front all the grounds connect at the bullet connectors by the battery. I think that they eventually ground on the 'breakfast' or grill. I had a reoccurring problem with my blinkers not working all that well. It ended up being the ground by the battery.

If no one has taken apart any of the electrical connections in a while be a bit gentle with them. Give them a twist before you pull.

Brent

[Broadstone]

I have chased a few electrical issues in the past. I usually start off simple by running a jumper cable from the negative battery post and use a length of wire or just a long wire and ground each light individually and use a test light. If they test as they should with the temporary ground you then know it is a grounding issue. I would check the ground attached to the breakfast as lanerover said, make sure it is a metal to metal contact, mine had a problem there due to new paint. Good luck, I find electrical issues the most frustrating but you will figure it out.

[LaneRover]

Just when it seems really overwhelming you will realize - in this truck it really is dealing with just 2 wires for any one light. It takes time and patience.

I think Broadstone gives a good tip about using a jumper line.

[HinFL]

Thank you LaneRover and Broadstone for your good advice. She is LHD so late today I took a quick look in the right rear wheelwell. I saw a wire bundle and a separate single wire exiting through a hole in the chassis and running upward toward the tail light assembly for that side. I was unable to locate any obvious ground to the chassis or rear crossmember nearby. I'll investigate that area further when time and lighting conditions permit, as well as check the breakfast ground and use the jumper wire technique. The PO installed rear work lights (which operate as advertised), so I'll also double-check any post-production electrical modifications while I'm troubleshooting.

Thanks again for the assistance.

Howard

[Billy5]

When I had brake light issues, by the rear light on top of the wheel well, remove the cover, and there might be a bolt there with ground wires connected. Thats where mine were. Hope that helps.

[LaneRover]

When I had brake light issues, by the rear light on top of the wheel well, remove the cover, and there might be a bolt there with ground wires connected. Thats where mine were. Hope that helps.

Come to think of it . . . Billy5 might be right. Just because the ground is where I think it is on my Rover doesn't mean its factory or where it is on yours.:rolleyes:

Goo luck!

[HinFL]

Thanks again for the responses and sorry it's taken me a little while for an update. As Billy5 suggested, I removed the light wiring covers on both sides at the rear of the tub. It's a rat's nest of wires back there! And to make the right side rat's nest worse, a 6-pin trailer plug is spliced into the wiring there. I found grounding locations at both rear corners. I don't exactly know how they work since they're up into the aluminum bodywork (another foolish question for a future thread). I've been hesitant to unplug any of the existing electrical connections, so as not to bugger it up any more than it already is. They don't look all that great, so probably they aren't.

One thing I have been able to determine: when the brake lights illuminate, the side lights come on at a lower intensity than they do when triggered by turning on the parking lights switch (i.e. step on and hold brake pedal and side lights illuminate, turn on parking light switch, side lights get brighter).

Sorry about the rambling, amateurish description, but didn't know if it would aid in troubleshooting from afar. Anyway, the present situation is of no consequence when driving at night because all lights work properly. And in the daytime, I could always drive with parking lights on...

Thanks again,
Howard

[HinFL]

During my troubleshooting, I broke a R wire from its bullet connector in the right rear corner of the tub. I replaced it and also another GP one using some di-electric grease in the process. On wiring diagram, GP wire is power to stop lamps and R wire is power to side lamps. Functional test showed all lights working properly! Very mysterious, Lucas...

Appreciate the posts that got me thinking and looking in the proper direction.

Take care,
Howard

[ignotus]

Howard,

I don't know if you have one but a test light is helpfull in working on the electrics.

gene

[HinFL]

Gene,

An excellent suggestion. As a matter of fact, I picked up a test light today along with the new bullet connectors. Didn't get to press it into service this time, but know it will get lots of use in the future with an almost forty year-old British electrical system...

Howard