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TR4/4A Wiring problem with TR4

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bluemiata90

bluemiata90

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I just purchased a TR4 and found that the previous owner had a electrical problem with the gauges(surprise?). Anyways, I've solved part of the problem after finding a burnt hotwire. The question I have is, on the back of the oil pressure gauge, attached to the hold down nut are three wires,1 brown and 2 black. When I turn the ignition on these wires are hot, are they suppose to be???. I've look on several color wiring diagrams and they don't show these wires. Any help would be appreciated.
 
I don't know the exact wire coding on your car, but black is usually ground & brown is usually hot. I would remove the brown wire from this connection. It wouldn't be unusual to ground instrument lights or gages as you indicate, but a grounded brown wire would be very unusual. You would have to trace the brown wire back to it's source, consult the wiring diagram, & decide where it should actually be connected. Unless, a piece of brown wire has been spliced onto the end of another color. Anything is possible from previous owners.
D
 
On a TR4, black should indeed be a ground, and brown should be hot. Looking at the wiring diagram, the only solid brown wire I see up under the dash should be wire running from the starter solenoid to the ammeter. Is it possible someone has mistakenly connected the wire from the solenoid to the oil pressure gauge instead of the ammeter? Are you sure you're looking at the correct gauge? It's easy to get turned around when looking at the gauges from the back side while essentially standing on your head. /ubbthreads/images/graemlins/smile.gif
 
I would take the brown wire off and see if it is hot. Check it with a meter or test light in each position of the ignition switch. If it tests hot, for sure it doesn't belong with the black wires. An extra brown wire hanging under the dash is not unusual.
 
I appreciate the replies. After reading the replies and reviewing the situation, I've decided the only way to figure this mess out is to unwrap all the wires and follow the wires. It seems that the ignition switch my not be the original and I did find a black wire and a red with a green or gray strip on the same bank on the ignition switch. Plus some wires are cut and taped. This is going to be fun (ha ha). Anyways, I'll let you know what I find out. Wish me luck.
 
Jim, I just looked at your site and it's great. What part of Chicago do you live in. I live on the southside and would like to ask you a few question about this TR4 if possible. My email is triumph61@hotmail.com. If you don't mind a few questions, give me a email. scott
 
None of the wires on the back of the oil pressure gauge are hot. None. You've definitely got something wrong there. As others have said, brown is almost always hot. The big gauge (smaller number) brown wires go to the ammeter, but you'd really be shorted out if one of those were involved.

You should be able to learn a lot with a test light and good wiring diagram.
 
[ QUOTE ]
...the only way to figure this mess out is to unwrap all the wires and follow the wires... I did find a black wire and a red with a green or gray strip on the same bank on the ignition switch. Plus some wires are cut and taped. This is going to be fun (ha ha).

[/ QUOTE ]

About the nicest thing I ever did for myself was put a new wiring harness on the TR3. Took very little time, looks great and no more mystery wires running around. I realize replacement harnesses aren't cheap but the results are a car that is better looking, more reliable and easier to maintain.
 
Geo, I agree and it just so happens that I'm restoring a TR3A and have already planned on a new wiring harness. I have the body removed from the frame and will rewire the car when all the frame, body and mechanical work is done. This TR4A will be a restoration project is several years, but for now, I just want to get it running correctly and have a little fun with it for the summer. The engine seems to run strong, so I don't think I'll have much trouble with it once I get the wiring figured out. The update is, today I found about 8 wires all wrapped together with electric tape under the dash, some of them hot, some, who knows.I did get the brake lights to work and found the problem with the hot black wires, but I still have alot of testing and rewiring to do. The previous owner had not idea of what he/she was doing and rewired grounds to hot wires, brake wires to running lights etc. You get the idea, hopefully by the end of next week I'll have it all figured out and working. Thanks again for the input. /ubbthreads/images/graemlins/smile.gif Scott
 
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