In a message dated 97-10-24 15:40:22 EDT, wave@ravenet.com writes:
> My 74 TR6 was backed into recently and sustained front damage. After
> replacing the headlights, which work, I noticed that the front signals,
> side lamps, and rear lights are out. It blows fuses and I'm having a
> hell of a time finding where it's shorting out !!! The two red wires
> coming off the fuse block ground out ...and also ground out at every
> point I check them along the front...though there are no shorts in the
> light wells themselves. Could a relay have been shorted to ground or is
> the red wire supposed to be a ground interrupted by a relay or
> something?
Will:
The red wires in your car - all red wires - are the source of power to the
lights you mentioned. If there is a ground on them anywhere, you will blow
the fuse, as there is 12 volts on the wires whenever the light switch is on.
> If I unplug the three wires from the light toggle on the dash, red still
> shorts everywhere. Should I try to bypass the relays next to the fuse
> block to test shorting?
Power is fed to the light switch from the battery via a brown wire, and from
the switch to the fuse box via a red/green wire. The relays are totally
un-related to the lights.
> There is a ground post in front of the radiator, in the same wire run,
> behind the grill, but this isn't a red wire....unless the red might be
> meeting it somewhere.
The red wires must NOT, under any circumstance, be connected to ground!
> Any advice is apreciated!!
This one is fairly easy - somewhere, AFTER they leave the fuse box, one or
more of the red wires is making contact with ground. It could be in the front
(most likely, since the accident), in the rear, or under the dash (the red
wire also feeds the dimmer for the dash lights). You will have to trace each
red wire untill it gets to a lamp, and then check the lamp holder for an
incorrect ground connection. You will have to do this by a physical
inspection, most likely, although it can be done with an ohmeter or a
continuity tester, with a little difficulty. Because the red wires are all
connected together, no matter where you place the meter, it will read a short
to ground, making it difficult to isolate the short.
A good place to start would be with the front fender marker lamps, as the
wires go through a hole in the inner fender to get to them. An accident could
very well have pinched a wire here. Wherever the problem is, you are looking
for just that - a pinched wire - as the most likely trouble spot.
Hope this helps.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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