Sorry for the long messages, but I just got the car and can count the time
spend enjoying it in hours (some would sy that I'm lucky) before it suffered
various breakdowns. Bleah.
In trying to figure out why my turn signals are too slow, someone suggested
making sure that the screws that hold the assembly on are properly grounded
to the body. The car had just been repainted, so I sanded some of the paint
off around the screws to make good contact, and it seemed to help a bit. OK,
I'll sand and clean more later. I went on to fix the left side and noticed
that someone had put rubber washers between the nuts and the sheet metal.
Hmm. It's a surprise that any of these lights work at all. How the hell are
these put together anyway? I went to get my spare assembly.
The rear turn signal assembly on a TR7 is constructed as follows. The lens
is a separate item, out of which stick all of the screws that hold everything
together. The screws are held solidly in the plastic, which is why one should
not overtighten the nuts, as the plastic itself is not that solid. Both of the
lenses on the car have little cracks around the screws. The reflector is a
cheap piece of metal, with chrome plating that flakes off the side that does
the reflecting, and either bare metal (for the ones that are on the car) or
some kind of varnish (for my spare one) on the back. The screws on the lens go
through a gasket, the reflector plate, a thick foam gasket and finally the
sheet metal of the trunk, star washers, regular washers and small nuts. The
sockets are meant to be grounded through contacts on the reflecting side
(inside) of the back plate, and have one wire leading to the centre contact
of the bulb, and possibly another which continues on to the equivalent lamp
on the other side of the car. The wiring harness is a pretty strange beast
(surprise). It's a ribbon cable which shows up on the right side of the car,
sprouts some wires for the right tail lamp, and continues along the trunk
to the left tail lamp.
One of the wires that goes to both lights is black, a ground, with a ring
terminal on the end This would lead one to believe that it should be held
onto the body around one of the mounting screws. This is where nothing makes
sense. Those screws are firmly attached to the plastic lens, not the
reflector plate. The screws can be made to have solid contact with the body,
by scraping off some paint and tightening the nuts down onto an exposed
area, but any contact that the reflector makes with the screws is incedental
(through the edge of the plate) and it is insulated from the body by the foam
gasket. Grounding by faith!
So, it would seem that the body is irrelevant in the scheme of gounding the
tail lamps. Oh well, time to touch up the new paint and reinstall the rubber
washer. One option would be to put the grounding terminal on one of the
screws, but between the foam gasket and the reflector so as to ground the
reflector. Being in the electrical business, I would like to think that the
ground contact is airtight, and not held in place by a piece of foam, and I
also wouldn't want the terminal's being there to comprimise the water seal.
But as I was looking for a hole in the reflector plate into which I could put
a screw to hold the ground wire properly, my boyfriend (with his head in the
trunk on the other side of the car) noticed a male quick-disconnect which was
attached directly to the reflector plate. This would be the perfect place to
put the ground lead!
Here comes the question. How did BL put these together? Was the ring terminal
supposed to be on the reflector side of the foam gasket, was there no
foam gasket, was there originally a quick disconnect and the previous owner
either changed it or put in the wrong wiring harness, or was whoever
designed this system truly a stupid git?
I never got to test the system with a better installation, as sometime during
this procedure, the car decided to stop charging (voltmeter needle at left
of centre when it used to be to the right of centre, and it's same with the
car running or not), and the signals don't flash at all. Arrrrggh!
Jody.P.Levine@hydro.on.ca - Toronto, Canada - 79 TR7 Ragtop
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