Electrical Problem Tail Lights Flashing with Turn Signals, no Brake lights
 

Hey yawl...

I installed a stereo in my old '89 pickup (SR5 3ve 4wd x-cab) and I have an electrical problem. I'm not SURE I caused it (I've done quite a bit of this sort of thing) but it seems likely given the timing of it.

The problem is this: When I signal a right turn, the two tail lights flash in sync with the turn signal (left works fine), and I have no brake lights.

I have removed the tail light assemblies, replaced all the bulbs with new, I have checked and replaced fuses in kick panel for "tail", "stop" and "turn", and removed and capped wires for my trailer lighting plug.

I have visually inspected all areas where I did any work, and see nothing wrong. I ran new circuits on separate fuses for the amps, and utilized existing wiring for the new deck.

(The only other thing I notice is that the factory clock seems very dim now, if that helps at all. It still dims farther with headlight activation, though.)

I'm suspecting a ground, or a problem in the steering column or at the fuse box, but I'm at my wits' end. I feel like it must be some simple thing, but can't find it. I would greatly appreciate any advice or suggestions.

Cheers!

....and you are sure it wasn't happening before the stereo work? Do you have a trailer light kit installed....they can cause crazy things to happen.

Tail Lights Flashing
 

Well, I disconnected the trailer lighting assembly and capped the wires as i said, and no, I can't be 100% sure it started then, but it seems very likely.

Thanks for responding. I'm going nuts with this thing,

FSM for the '90 may help on your '89 and least in the electrical trouble shooting area (not sure what difference pick-up vs. 4Runner introduces):

http://www.ncttora.com/fsm/1990-1995...5/contents.htm

Thanks. I think this might help. The manual I have has much less detail. I just know it's some simple thing somewhere, so I'll get to checking splices and relays.

I really appreciate your help.

Start in any of your stereo work areas and move out from there. Post up where you find it for future reference.

Problem Solved
 

Well, if anyone is interested, I finally figured it out.

As I said, I first went to fuses, then bulbs, then removal of trailer plug, and then disassembly and reassembly of tail lights checking for shorts or any wiring problems.

I visually inspected the wiring running along the chassis, and although it was hard to see every part of it, especially around the fuel tank, it seemed okay.

Then, as I had had a lot of the dash assembly out recently (when I installed a new stereo, fixed the fan, replaced a broken speedo cable, and other misc, stuff that had accumulated on this fine vehicle), I pulled the dash sections out again to see what I could find.

One thing I believe I neglected to mention was that after my re-assembly of the dash the first time, I found the fuel gauge had quit working. The signal lights and flashers were all working properly.

Exasperated, I disassembled the dash enough to inspect the instrument cluster. I couldn't find a problem, and gave up for the time being, figuring I had a trip meter, and thought maybe something coincidental had happened with the sending unit.

I didn't check the signals again after that. It was a month later when I realized they were not working properly.

I had spent hours on it, and was just about to give up, when I found the problem. I was under the truck just checking the undercarriage wiring one last time, and right where the wire raceway penetrates into the passenger compartment, I caught a glimpse of copper. The wire was caked and beat-up looking all along its length, so it was just luck my light caught it.

It didn't appear that the edge of the hole in the sheet metal had done it; the grommet was still there. Possibly a road hazard, possibly me, although I don't think it was. It was a little v slash, and when I exposed the conductors and soldered them up correctly everything (even the fuel gage, as the sending wire was in that raceway) worked.

Dumb. It was an obvious place to inspect more carefully before disassembling th that %##@# dash for the third time.

Cheers!

Glad you got 'er fixed! Thanks for posting the resolution.

Grouchy- I have the same problem with my 04 Taco. By chance did you have a clicking sound that was unusually loud when you turned on the emergency lights. The sound is coming from under the shifter right above the tranny. I have tried everything and am desperate to resolve this issue. Also it cuts off the cruise control when I turn on the right signal and do not have any problems with the left signal.

I have tracked down where the problem is located but need help diagnosing. It appears that the automatic shift lock relay is being activated (clicking on and off) when I turn on the left signal or the emergency lights. It for some reason is causing the tailights to flash at the same time. Has anyone had the same problem? How to fix it?