[urq] Dim Tail Lights

[urq]

I sat down with the wiring diagram and remembered that many of the
connections for the right light plate are made via the left light plate.  If
you have resolved the ground issue (with the lights on you may want to
measure the voltage drop from the car body to the ground point on each light
plate to be sure), my next suggestion was to clean up the electrical
connections at the connectors to the light plates.  You might start by
checking voltages at the left and right sides to verify there is drop
between the two.  These connections are from copper to galvanized metal, so
any moisture can cause oxidation.  If you expect a moist environment in the
trunk you might want to coat the connector surface on the light plates with
Vaseline (or insulating grease) before reconnecting the loom to minimize the
effect of moisture.  

 

The wiring appears to be direct from the fusebox to the back of the car, so
you don't have to worry about intervening connectors going bad.  You can
check the supply voltage at the fusebox . it looks like fuses S13 & S14
supply the tail lights . if you see low voltage there you want to look back
towards the switch.  Of course the switch is old too and subject to contact
resistance issues.  Recently I cycled the headlight switch on and off a
bunch of times to brighten up my running/tail lights after the car had been
sitting a while.  It is not that difficult to get to the switch to spray in
some contact enhancer if you'd prefer.  

 

Steve Buchholz

 

From: dgraber460
Sent: Friday, March 07, 2014 6:15 PM
Subject: Re: [urq] (no subject) & Dim Tail Lights

 

Thanks Steve. 

You're right, and the more I thought about the relay idea the more I
realized it wouldn't work very well, as all 3 signals to the lights would
need their own relay. (running, signal, & brake) I'm going to dig deeper
into the entire wiring situation including the grounds and chassis contact
points.

That has to be it as it isn't sporadic - just low constant voltage.

Ah - the love hate relationship of old cars. I do really love this old thing
though.

Dennis 

Denver

 

-----Original Message-----
From: urq 
Sent: Fri, Mar 7, 2014 4:56 pm
Subject: Re: [urq] (no subject) & Dim Tail Lights

=====

... administrator's note ... to eliminate empty subject spam sent by list
members (which was once rather common) any post without a subject is
automatically moderated (held back for approval).  Fortunately I saw this
one and got it posted quickly ... 

=====

If you have not improved the grounding of the tail lamp mounting plates by a
direct connection to the unibody, doing so will likely brighten up your
lights significantly and sufficiently; that is the solution I would heartily
recommend.  The lights you aren't thinking about are the brake lights ...
and these use a lot more current than your running lights.  Relaying the
power to the running lights won't help your brake lights at all.  Tail
lights are what, 5 watts?  Relaying such a low draw seems pointless to me
... 

 

For better or worse the original wiring of the car has the ground return
coming back through the loom ... which means that you've got as much voltage
drop in the return as you do in the supply ... even more so when the brakes
are applied.  

 

The updated dual, dual filament bulb mounting plates have a tab on the
ground "trace" to allow a slip on grounding lug to be used to provide a
direct connection to the body of the car.  I don't remember if the single
filament plates have a similar feature or not.  I used one of the mounting
studs for the lens to connect the updated grounds on my car.  Be sure to use
a star washer to make sure an electrical connection gets made through the
paint of the unibody (install the star washer against the unibody, don't put
any other sort of washer first).  

 

I remember following Tomas K's car up to Thunderhill many years ago.  He had
sprayed the lenses to black them out ... and on a foggy morning in
Califonia's Central Valley I realized how poor the visibility of those
lights can be.  The dual, dual filament tail light mounting plates make the
car much more visible from behind ... and they are a direct fit for the
original lenses ... highly recommended.  I wonder if newer cars (like say
the '86 CGTs) received these bulb plates from the factory.  I got the set I
have on my car from a GB years ago.  

 

So, don't worry about adding relays, at least not at first.  Start by
improving the ground.  It probably won't hurt to clean the oxide off the
connections at the tail light mounting plates ... there'll probably be a bit
of a dissimilar metal corrosion there.  

 

Steve Buchholz

 

I remember one day I found myself with several officers from the SJPD behind
me ducking behind the doors of their squad cars, drawing down on me ...
because someone riding a blue motorcycle had robbed a bank ... 

From: dgraber460
 Sent: Friday, March 7, 2014 11:49 AM
 
New URQ drama. Not really too dramatic but anyway......
This morning I'm cruising down the road at 2 below the limit being a good
boy, and a patrol turns right about 1/4 mile up the road. Right behind him
another car pulls out in front of me without stopping for his red light. I
ignore both and continue on my way. The patrol car starts slowing down, and
I surmise he is going to duck behind the other car and get him for a red
light violation. Nope! Slows down, ducks right in behind me and turns his
lights on. When he approaches the car I have all the normal paperwork ready,
and he tells me he pulled me over for a right tail light out. He goes back
to the patrol car per usual to check me for "wants & warrants", after which
he comes back and warns me to fix the light. I'm thinking to myself that
there was no way he could have known the light was out until he pulled me
over. He was NEVER behind me until his lights were on.
No ticket and no problem, just very odd! Later going back on the same road I
saw another older Audi pulled over and was wondering if they were looking
for a perp in an old Audi for something else?
Anyway - so I get home and try to check the offending right tail light and
sure enough it's out. As I start checking, I find that I only 7.5-8 volts at
both tail lights, so the left is pretty dim as well. Is that the light
switch on the dash causing this and I just need to relay the tail lights
like I have the headlights? Since the battery is just ahead of the bulkhead
it would n't take all that much to do it.
Any usual suspects or fixes/workarounds?
TIA


Dennis 
Denver