ULpilot

I've been having an intermittent problem with my right (passengers) rear taillight. Now it's always off.... and I need to pass an inspection this weekend.
I'm thinking it is the ground, and just discovered that the 86.5 doesn't have the ground point back right in front of that tailight.
I found this in the archives http://members.rennlist.com/v1uhoh/groundpoints2.jpg
Now I'm wondering- which ground do I need to clean up, which ground point is the ground for these lights? I think it's the ground- I've lost right rear side marker, right rear brake (I think), and RR tailight for when the lights are on. The blinker works fine though. Any advice? I'd appreciate a push in the right direction. I found some good stuff in the archives, but I'm still confused.
Thanks!
Simon

MarkRobinson

check all your fuses first, pull them out, inspect, put them back. a flashlight & some needle-nose pliers are a must. Use a folded up towel to save your knees. There are fuses that link an item that also link items not listed on the fuse charts.

Also, double-check that all your bulbs are of the correct wattage: there are number of bulbs that will fit the 928's housings, but have different wattages that will quickly lead to issues/popped fuses, melted taillights, etc. Most "normal" bulbs are "american-spec", not "european spec". Check the book at the autoparts store for your car, & pull all the bulbs, then jot down all the wattages & go out & check your bulbs. My ABS didnt work for a year, couldn't figure out why (light on the dash), then pulled a bad tail light bulb to find an "american-spec" bulb, replaced with the correct "european bulb", the ABS light went off.

wierd birds indeed.

Mrmerlin

Hi if you look on the bulb housing it should give the correct wattages for the bulb position to fix the rear side marker check the fuse first then turn on the parking lights and open the hatch lift the carpet and look carefully around the corner of the light that is not working you will be looking for a white connector that has 2 wire going to it disconnect the plug and reconnect while watching the side marker, if the connector is dirty then you will probably see the light come on, water seems to get into the rear hatch area and is gets into the white connectors and corrodes them clean the connections then use some Dielectric grease on the connectios do both sides, if still no joy get the test light out and see if you have power going to the lights, to find the ground just follow the harness I think that ground is in the forward part of the spare tire well under the plastic cover on top and in front of the battery well cover

kraabel

I tried for 8 months and could never figure it out. But in case you're wondering and you need to pass the test, you can tap into the power from the other side and run it across with a splice just to pass inspection. Once you figure everything out, drop the splice and back to normal.

tomcat

I had a problem with my taillight when I first got my '85. Found out the light bulb was the wrong size (I think wattage because the brightness was not correct). I think the break light and taillight are different bulbs - at least in my case.

ULpilot

Checked things over more today. The brake light works, blinker, and backup. It's just that the side right rear marker, and the rear running light don't. I cleaned the ground in front of the battery, it should be fine. Pulled and checked all fuses, they should be good. Checked bulbs- it's 21 watts for the tail, and I just replaced the other marker (it worked with this one for a while, but I'm not positive this is right- even if it's not, shouldn't I see a blown fuse or something somewhere?). Unplugged things from behind the quarterpanel trim piece, but DE grease on them, plugged back in, still nothing. I'm lost.
Checked the sockets with a multimeter, and am getting .2-.4 volts through both the marker and the running light. Any further hints?
Thanks,
Simon

tomcat

Simon,

Did you try replacing the right with the left bulb? At least you can eliminate the bulb as the problem.

ULpilot

AAARRGH
Switched bulbs to test- and yes the bulb works fine, no problem there. I decided to flip on hazards to ensure that the blinker was working. Now the front 2 blinkers went on, the back 2 stayed off. Try on just blinker settings, and same thing- front ones work (double speed) back ones don't work. This is more than slightly frustrating. And this is probably just the begenning of my electrical adventures!

neilh

simon, do you have the wiring diagram? If it is a bad ground you can jump out the ground at the light cluster to eliminate that. at least.

BTW, like your vehicles in your signature, I have owned all of those ( brits) also plus lotus cortina, you must be a limey!

Neil
ex pat.

Alan

Simon,
If you have 21W bulbs in your marker lights you could have a blown fuse otherwise the only difference front to back is that the rear markers are supplied though the bulb monitor.. check the connections... you will have been overloading the resistor - especially if all your markerts are 21W...?

Its possible you may have damaged it (though I'd think its unlikely)...

The markers should be 5W bulbs - only the brake/turn & reversing lights should be 21W. (Brakes are dual filament with a marker (USA only) 21W/5W.

You have seperate left & right marker fuses.

If a fuse is out you should get 0v on the +ve feed for that bulb - but with a shared ground (and another bulb on) you will see the ground at the bulb move up a little due to voltage drop in the shared ground wire...

Alan

JG928S4

I had the right rear blinker go out last week, changed bulb and fuse, and connections on single bulb housing, no workie, then un-plugged and cleaned the one plug that goes to the complete rear tail light and then it works!!

SMTCapeCod

Sooo frustrating when you finally found a dusty thread with the same model year, identical problem (well, my plate lights are out too) and no solution/closure.

Grr, finish 'em up people!

Mike Frye

ha ha. Sorry, I feel your pain.

I would say that about this time I'm sure there were a few similar threads (it's when I started having problems with the same thing). One thing I remembered learning was that the bulbs need to be replaced in pairs. A new one and an old one (even of identical wattage) can cause this kind of thing. I know he said he tried the right bulb in the left side, but didn't say whether they were both replaced at the same time.

I'm sure the answer was to keep cleaning contact points and grounds until it cleared up. That's always the answer.

Hold On

I have had the same problem with the same light. Mine turned out to be at the small barrel connector were the light housing plugs into the harness. There are multible ground (brown) wires attached to a single pin. The pins are very fragile and one was broken inside the plug. This created an intermittent ground/no ground situation that drove me nuts for a year. Also several needed cleaning. May help, Good luck.

SMTCapeCod

Thanks, both of you- a bit of wisdom and a bit of a plan.

I actually went back under the quarter today-- the expedient way-- to feel around and make sure I wasn't crazy about not having the rear quarter ground. But I expect that cars that do have the tire well ground, lack the quarter ground. Could be wrong. Saw a lot of threads about a two pin connector under the carpet, but I think that is older models, no dice there yet.

Hate these niggling faults....not that I like the bigger ones either.