1971 Fuse Box and Wiring

[Tearful Owner]

I hope this is correct thread, but if not will try another. I have a 1971 Triumph TR6 and have been messing with it for years. Over the last few months I have paid someone to allegedly fix all of the wiring issues. Sad to say I wasted my money so I decided to start fresh! I purchased all new gauges, lights, relays, and fuse box as well as turn signal switch and headlight switch. Therein lies the problem. I had all of the "stuff" working, to include high and low beams, but couldn't get the flashers and turn signals to work. Checked the massive maintenance manual as well as wiring diagrams from Autowire. Poured over them and it seems I've now lost everything trying to get the flashers and turn signals to work. Tracing wires etc, I think I've found two possible culprits. Don't which came first the fuse box or the headlight wiring. But my real mystery is that there is no current coming in or out of the red fuse link(first fuse on the fuse block going n/s) One side is the auxiliary lights (double red wires) and the other side is the red/green wires. I did a jumper wire from the headlight switch wires to the red/green fuse box link and attached it as well to a always hot battery fuse block (for fog lights and a couple of accessories). Current flowed to the headlight switch so I figured the wires were good but as soon as I took the jumper off the two fuses boxes no current again from the fuse box either in or out. Just can't figure where the current is going or not going! Burned up one headlight switch by a short when checking continuity so I'm wondering if something or wire is burned somewhere where I can't see. Wow, lot but if anyone has an idea as to why no current is going into or out of the first fuse link on the fuse box I'd appreciate it immensely. Tried switching wires for the red/green link and the red link. Moved them down one fuse and the wires that were there I moved up one link but still no current. Fuses age good, though I have blown a few. Again, anything else I'd appreciate thoughts. Frustrated as H H.

 

[JPSmit]

There is little as frustrating as wiring issues. Much of what goes wrong with these cars comes down to grounds (black wires). That said, do you have a multimeter and a continuity teseter? (you don't really mention either in your descriptions. If you don't you really need to get them as testing this all while the battery is conected is a recipe for letting the smoke out of the wires - don't ask me how I know. Good Luck!

 

[auprichard]

Having spent a year wiring a car, I second the sentiment about wiring frustrations. It is also incredibly difficult to advise from afar. Do you have a local Triumph club where you could organize a tech session and get a few extra bodies to work out the issues?

 

[TRopic6]

Hi TO, auprichard is right - very hard to advise without eye-on. You said it all the stuff was working at one point, "but couldn't get the flashers and turn signals to work". The hazard flashers and turn signals BOTH get power through the dash rocker switch between the tach & speedo. Study the Advanced Autowire diagram for 70-71 TR6, lower right corner. The turn signal column switch gets power from a light green/brown wire via that switch. The hazards are powered from a purple wire (always hot) so they can flash at any time. A relay is also needed to get both sides (4 lights) to flash at the same time. Each system has its own 'flasher' to cause the lights to blink.

The dash hazard switch is often behind turn signal & emergency flasher problems; cycle it a few times to clean the contacts. Pop it out of the dash and check for power. You can connect the appropriate wires together to power up each system seperately to check operation. Study the wiring diagram and trace each circuit.

Jeff

 

[Sarastro]

Jeff is quite right--there is no way for any of us to give you more than a blind guess without actually seeing the car. So, this is one you will have to handle yourself. (Hint: these cars' electrics work fine when wired right. You've got a wiring error somewhere.)

But we can help, if obliquely. Start at the battery and follow the circuit with a wiring diagram and a voltmeter. Make sure you are getting voltage wherever you should, and find the point where you are losing it. It's really pretty simple; just apply ordinary logic: you're getting 12V at one point, then no voltage at the next point, so the problem must be between those points. And, yes, be sure you have good grounds--clean, metal-to-metal contact.

Also, if you have one, use a small storage battery instead of the car battery when you are troubleshooting new electrical wiring. Less chance of frying something.

I'm a professional electrogeek, so I could be accused of making light of this. But I'm continually amazed at how people will tear down a carburetor or transmission without thinking twice, but when faced with an electrical problem, they get frightened. No one has ever invented a test instrument you can stick into a carburetor or transmission to see what's wrong with it, but we have one for electrical systems: a multimeter. With that, a wiring diagram, and a little logical thinking, you can fix anything.

 

[Popeye]

But I'm continually amazed at how people will tear down a carburetor or transmission without thinking twice, but when faced with an electrical problem, they get frightened. No one has ever invented a test instrument you can stick into a carburetor or transmission to see what's wrong with it, but we have one for electrical systems: a multimeter. With that, a wiring diagram, and a little logical thinking, you can fix anything.

Make sure your multimeter measures “smoke”.

You put it well - I completely agree with what you say above.

My background is mechanical, and am intimidated by electrical work. But with a bit of patience and thought before tackling a problem, so far I’ve worked through all of them. I can’t stress the value of a functioning multimeter… I’ve had bad experience with cheapies, and splurged on a fluke a few years ago.

(Which gets me thinking: what are units of “smoke”? Local resistance (ohms) vs. flammability…)

 

[mctriumph]

When I re-wired my 71 , the final problem was that the turn signal flasher had a
discontinuity (broken wire) inside the brand new harness. I cut to the chase by installing
a 3 prong flasher from the Tr3/4 to the column where the wires come from the switch
This was plug and play ,working perfectly for years and needing NO cutting/splicing.
Mad dog

 

[Deleted member 12064]

If you do not have Dan Masters 'yellow' book consider a purchase or his online version. I prefer the book.

Dan Masters Yellow Book

A tool I find that has helped me the most is the Power Probe.

Power Probe