rAvery

Hey all, I am having an issue and hope someone can point me in the right direction. I ran some searches, and checked my FSM and Chilton, but I am still stumped.

The other night it was brought to my attention by a friendly CHP officer that my tail lights are not working, I got a nice little fix it ticket.

The turn signals and tail lights are not working, but the brake lights are working fine.

I checked the bulbs, all were OK, but bought new ones just to be sure. I tested all of the fuses, and they are good. The wires going to the tail lights seem OK and not damaged from all that I can see. Recently I had to install new plate marker lights as the PO put on a new bumper, but did not replace the lights. I found the wires for the old lights still connected to the old housing which was duct taped to the underside of the bed. I am not getting any current from them. I have been using a testing light to check, but am getting nothing from the old lights. I feel like the issues may be related, but I am not sure. I have not made any changes to the wiring or added aftermarket items since I got the truck.

IF anyone has any ideas I would be eternally grateful.

CJM

Do you have a trailer harness on there? I had an issue on my T100 where the dash would blink and the signals wouldnt work and neither would the brake lights. Unplugged the harness and bingo. New harness solved the problem.

rAvery

I have to connectors for a trailer harness, but I do not have anything connected to it.

The front turn signals do work, if that is helpful information. The dash lights for the turn signals are also working fine.

CJM

If they are the type that plugs into your tail lights then the tail light connects into that remove them and see.

rAvery

What do you mean by "they"?

The trailer wiring connector comes off the same bundle of wires that the driver side rear turn signal connects to. The connectors that go to the turn signals are a different type than the connection to the trailer wiring harness. The plug for the trailer lights is just hanging off the bundle of wires. I have no other connecter like it on my truck.

I just thought about this: A few weeks ago I put a set of bucket seats from an 87 S-10 in my truck (The bench seat that came with the truck was murdering my back). I know there is a set of wires running along the top of the frame coming from the passenger compartment going back to the tail lights. I could have possibly knicked that bundle of wires with the drill while I was mounting the new seats. If i did hit this bundle and have to run new wires would I have to splice in a new section, or would I have to run new wires the whole way?

wyoming9

iTrader: (1)

Do you never check things or wait to get a ticket??

If you indeed damaged the harness it depends just how bad .

I have seen drill bits get snagged on wires and make a major mess .

You will just have to see .

Splice in some short pieces or replace the whole harness.

please let us know how you make out!!

rAvery

After I thought I nicked the harness I checked the lights, and they all worked fine. That was about a week ago. I do not check the lights on my vehicles too often. Maybe once a month. My weekly checks are fluids.

I have not had my Toyota for very long. I got it back in the beginning of June. 28 days after I bought it the head gasket went. It sat for about 2 months before I could raise the funds for a new engine. It has been back on the road for a month now.

Tomorrow I will try to replace that section that go nicked by the drill bit. I will post an update tomorrow. Hopefully I can get this figured out soon. Not being able to use it at night is a pain.

Thanks for all the help so far.

hossdog

I had the same issues on my 84 and couldn't find anything. Finally just went through every connection I could find cleaning and greasing. Also went through the brake pedal switch and through all the connections at the column and fuse boxes. Still never found the cause of the original issue, but everything works great now. Really not complicated takes a few beers, and some patience.

rAvery

Arrgh.
So I have checked the tail light fuse. Fuse is good.
Replaced the Tail light relay. No change.
The switch seems to be in proper working order.
So I think I am down to a bad wire or ground. I am just having difficulty finding it.
I bought a Voltmeter, but I have no idea how to use it. I am looking at youtube videos on using it now. If anyone has any tips on using it I would appreciate it.

RAD4Runner

Wanna re-state your problem/symptoms in one place so those trying to help don't have to jump around the thread?
A problem well-stated is a problem half-solved.

Did you check all the bulbs?
Turn signals are not working but front signals work?
Dash turn indicators working?
Front markers working?
Taillights working?

Before you even need the multi-meter, use your senses (sight, hearing, feel...):
Taillight relay clicking?
Flasher relay clicking?
Dash lights working?
Measure resistance across each bulb?
Measure Voltage at each and every bulb connector that is not working when it's supposed to be on/ To measure voltage at connector:

1. Remove bulb,
2. Multi-meter on and in Volts DC 20V range or closer but not less than 12V.
3. Red (+) probe at middle contact of connector.
4. Black (- or Gnd) probe at outer contact of connector (metal that wraps around bulb when it is inserted).
5. Turn that light on.
6. Reading?

Tail lights and turn signals take power from separate circuits. Need to troubleshoot separately. However, a resounding However, IF they both do not work, find what's common between those that do not work.

If front turn signals / lights work what could possibly keep power that goes to front lights from getting to the rear lights? Broken wires between front and back?

Check the obvious.
Possibly the wiring that you hit with the drill? BINGO!
How do you find a bad wire? By digging into the harness and inspecting each individual wire.
Sometimes pulling a wire may not break the insulation but it would break the actual strands inside. Here you're gonna need the multi-meter to check for resistance or voltage.
Got a schematic? Post it so we can tell you where to probe?

Gotta be careful were you drill.

rAvery

Finally got it all worked out today.

Rad4Runner, you were totally right. When I drilled the new hole for mounting my seats I did end up tearing one wire in half and damaging the insulation on another. The wire that got halved was a green wire, once I got it back together the lights were working. I can finally drive the thing at night.

Only issue is now that I got that fixed the lights on my instrument cluster have gone out. Now I have to go back and start all over again.

Thanks to everyone who was kind enough to lend a hand.

RAD4Runner

Glad you found it. Instrument cluster also takes power from Tail Light Circuit. That green wire supplies 12V from tail light fuse. Schematic's too big to display on forum page so just click this for full-size. Basically trace green wire from tail light fuse in driver side kick panel to dash and find where it broke. You light also want to check for ground for dash wire. I believe it also goes to the chassis ground bolt near driver side kick panel.