Rear Brake Light issue, need some help please (1 Viewer)

[StressPuppy]

Did some research and not finding anything exactly like my issue, so hoping someone can help me. Seems it is an electrical problem of some sort (YUCK) but having trouble tracking it down.

If my headlights are off, when I push on the brakes, the clock like and radio backlighting dim. Cig lighter light comes on and the running lights on the outside come on.

If my headlights are on, rear brake lights are on all the time, but when I press on the brake pedal, nothing on the dash dims/changes.

I pulled the stop/brake switch and tested it as per the factory manual. Pins 1 and 2 have continuity and when you press in the button, continuity gone. But something is obviously wrong. The fact that it is relate to the headlights and dash lights makes me think a short, but there are so many dang wires under the dash, not sure where to begin!

Any one had this issue? Where do I start? If it is a short, how do I track it down?

Thanks!

 

[retrofive]

Do you have any trailer wiring? one place to look.

 

[StressPuppy]

I do have a connection for a trailer back there. Has been there as long as I have had the rig, never had an issue. This just started happening in the last few weeks. You saying a short in the trailer harness would cause this behavior?

 

[retrofive]

I don't have any first hand experience with it, but reading through the forum your "short" or what it may it be sound like a likely cause. Behind the inside rear quarter panels where the cabling runs for the rear lights, side markers, etc is where there has been issues, esp with aftermarket trailer setups. Seems there has be plenty of "shorts" in that area which cause all types of odd effects.

Even if its been there for someime, it could have got crimped, broken, shorted.

Just my 2 cents and an idea . Honestly don't know, but something I would look at.

Good Luck

 

[StressPuppy]

Hey, it's more than I thought to look at, so I appreciate the input. I'll give it a look and see. Thanks!

 

[80t0ylc]

Your only problem is a short between brake lights and your marker lights. Your clock and radio lights will normally dim when you turn on your marker lights. The marker lights normally stay on when you turn switch all the way to headlights.

Have you done any mods to your brake lights or marker lights?
Have you done any thing where you might have crushed a wiring harness?
Have you recently changed any light bulbs. A bad or wrong type of light bulb can give you a short or feed back into other circuits?
Have you done any wheeling and submerged light fixtures which might still contain moisture and are shorting out?

If you suspect bad bulb(s) take off your lenses and start removing bulbs one at a time and leaving them out until you find the culprit. Good luck. Difficult problems demand persistence.

 

[East TN LC]

Same electrical problem...........

I have been having the same problem for about a month. I hate electrical issues. Previous owner (?) made a mess of trailer wiring. Insulation is rubbed off newly added trailer wires where they pass through the body near/below the DS tail light. Any help is appreciated on this issue. I will post revelations.

 

[StressPuppy]

A bit over due and thread is old, but thought I would update what I did to fix the problem for anyone else that may run into this.

Taking advice from others here, I pulled off both rear tail lights. With the LC running, I applied the brakes to see if I got the problem. Of course I did. I then took out one brake light, tried the brakes again. If the same result, I put the bulb back in. I did this a couple of times and on one of the bulbs, when I took it out and applied the brake, everything worked as it should. To check, I put the bulb back in and problem came back. I then put a new bulb in and everything worked. The odd thing was that the bulb itself was coming on and was of the right type (or so I remember).

Hope that helps someone else as I know I was pulling my hair out (well, would have if I had any! )

 

[80t0ylc]

Good job! Glad it's fixed and now you have the satisfation of having done it yourself. BTW, you should also be commended for giving update/feedback! Quite a few don't bother to give results, even when asked.

 

[95ToyCruiser]

I had the exact problem as well, here's what it took to fix mine:

I ended up fixing mine last night. Mine wasn't so simple, the main plug behind the right rear interior pannel under the jack holder was very corroded and 2 of the pins were shorting out with eachother (I assume the brake and running lights). So I had to cut them and jump them over the plug.

Shane

 

[80t0ylc]

I had the exact problem as well, here's what it took to fix mine:

I ended up fixing mine last night. Mine wasn't so simple, the main plug behind the right rear interior pannel under the jack holder was very corroded and 2 of the pins were shorting out with eachother (I assume the brake and running lights). So I had to cut them and jump them over the plug.

Shane

Shane, is that compartment filling with water? There's plastic drain plugs at the bottom that might be blocked with dirt/crud. Rear window trim strip tabs leaking can cause excess water in that area. There's good threads that will describe this - search on rear window, rear sliding window or sliding window in titles only in 80 forum. I think other sources for water could be leaking tailgate and/or the rear sunroof drain hose goes thru here, also. Reason I mention all this is the problem you fixed is a symptom of another problem. HTH