• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR6 '74 TR6 Fuse Box [UPDATE] SOLVED!

Share this page

WidespreadPanic

WidespreadPanic

Jedi Hopeful
Offline
so I replaced my fuse box and now the only lights that work are the headlites. The car starts fine, but no marker, tail, dash etc. lites. I suspect I may have flubbed in making the change over, as careful as I tried to be in making the change over. (I know, I know, I should have snapped a pic at the time but I didnt, it seemed like an easy enough task to do with out messing it up).

Here's a pic of what it looks like now.
000_0275.jpg


Does anything look obviously wrong with that? I will further say that I dont think the wiring in this car is original, I believe the harness was replaced about 10 years ago.

Thanks for any help you guys might be able to provide.

Do any of you have a pic of a late TR6 fuse box that might help me fix this issue?
 
Re: '74 TR6 Fuse Box HELP!

on the power in side try moving all the connections up 1 spot. Don't know if it will work but it might.
 
Re: '74 TR6 Fuse Box HELP!

The connections look good - according to Dan Master's diagram for the '74, the two green connect to the white, the four purple to the brown and the two red to the red/green.

The schematic shows that the healamps are on the purple circuit. The front and rear parking, markers licence plate, and gauge illumination lamps are on the red circuit. Do the indicators work (these are on the purple circuit also)?

I'd check the connections for the red/red-green circuit, and also that the fuse is good. Good luck!

Mark
______________________
1976 TR6
 
Re: '74 TR6 Fuse Box HELP!

I'm with the relatives at the moment, but I can take a pic of mine and post in within the hour when I get home.

Since my posting the above post moved in and relates to the Masters book and that says it all.

Just out of curiosity, what type and rating fuses are you using in the the new panel? I hope that those aren't 30 amp US rated fuses that I see.
 
Re: '74 TR6 Fuse Box HELP!

I posted my reply from Dan's diagram.Do you have it??
 
Re: '74 TR6 Fuse Box HELP!

All you should have to do is use a test lamp to see if the circuits are being completed across the fuse box. The brown is always hot, the white works off the ignition and the red/green works off you light column light switch. Your bottom fuse looks different from the other two. Are those Buss (American) fuses? You really should being using only Lucas 35 amp fuses in all three slots.

Sure you didn't mess with a ground somewhere? Sounds like you might have knocked a ground loose somewhere.

Even if you didn't undo a ground, it is possible that a ground wire is really corroded somewhere. Start looking around.
 
Re: '74 TR6 Fuse Box HELP!

[ QUOTE ]
Just out of curiosity, what type and rating fuses are you using in the the new panel? I hope that those aren't 30 amp US rated fuses that I see.

[/ QUOTE ]

Those fuses are what my local Brit shop gave me. The car is over at my off site garage, so I can't check it till the morning, but I doubt they'd give me incorrect fuses.

I'm impressed that you check this forum while you're at your relatives. /ubbthreads/images/graemlins/wink.gif
 
Re: '74 TR6 Fuse Box HELP!

I just went and looked at my fuse box. Those are Buss fuses you have there. Very possibly way overrated for your harness.

You really should be using a simple lighted circuit checker with an alligator clip and needle-sharp pointed end.

Start looking for grounds.
 
Re: '74 TR6 Fuse Box HELP!

What your pic shows is OK. I think the wires should be moved up one slot, but they are OK as they are. Since your headlights work, we know that power is getting to the headlight switch. Since the tail, marker, and dash lights don't work, we know there is no power on the red wires. Power to the red wires comes from the headlight switch via the red/green wire. Somewhere between the red wires on the fuse box and the red/green connection at the headlight switch there is a break in the wiring.

Check to see if you have power on the red/green wire at the box (with the light switch on). If you do, then there is either a bad fuse or a bad connection on the fuse terminals. If not, then go back to the red/green connection at the headlight switch and look for power there. If you don't have power there, then the headlight switch is bad. if you do, then there is a breal in the red/green wire between the switch and the fuse box.

ie, power comes from the battery to the headlight switch, from the headlight switch to the fuse box via the red/green wire, through the fuse to the red wires, and through the red wires to the lights.

It won't be a ground problem unless you simultaneously have bad grounds on all the bulbs.
 
Re: '74 TR6 Fuse Box HELP!

Family business, office at main compound. Good excuse to check email while on a break after dinner and dessert. Just happens that the browser opens to the BCF Triumph Forum. What a coincidence!

TR6Bill has the 12-6 night-owl shift, I'm only on from 3-11 with DNK. Tinster is the early bird on the island of Puerto Rico, posting at the crack of dawn.

I agree with Bill about the test light and the ground. Doubtful that you'd have a break in the fuse panel, but that will tell from one side to the other. then go for the grounds.

Good luck!
 
Re: '74 TR6 Fuse Box HELP!

WidespreadPanic
here is a pic of my '74 TR6 fuse box. My wiring is original as is the fuse box. Standard fuses are installed at 30Amp for all. You may have a bad earth somewhere (or several bad earths). Check all those first. My tail light and head light earths come loose often.
Regards
Craig
 

Attachments

  • 283899-PB240001.JPG
    283899-PB240001.JPG
    87.4 KB · Views: 871
Re: '74 TR6 Fuse Box HELP!

ok so I ran over to the garage and did some additional checking. The bottom fuse (red > red/green) keeps blowing when I turn on the headlites.

I tried to read the info on the fuses but my eyes are just too poor for that right now. Maybe in really good daylight.

And here I thought I had dodged the ever feared TR electircal demons, as to date I have never had any problems with my 6.

Any ideas on why the bottom fuse would suddenly start blowing after installing this new box?

Thanks for ALL your replies. You guys are great. /ubbthreads/images/graemlins/cheers.gif
 
Re: '74 TR6 Fuse Box HELP!

Oh-oh. I don't like the sounds of this. I thought that the headlights were working OK and the other lights were the problem.

Are you sure that no wires are touching and that nothing else was disconnected during this fuse box swap out?

And DO NOT go to any heavier or higher rated fuses until we get this resolved.
 
Re: '74 TR6 Fuse Box HELP!

the headlites are working just fine (they're on the purple) The schematic shows that the headlamps are on the purple circuit.

Its the red > red/green that are blowing now. The front and rear parking, markers licence plate, and gauge illumination lamps are on the red circuit.

I'm not putting any more fuses in.

What is the significance (if any) of connecting to the front or back tabs on the fuse box panel, in the instances where there is only one set of wires on that circuit?

For example, on the bottom (red) circuit, should the power side and the component side both use the same (forward or rear) tab?
 
Re: '74 TR6 Fuse Box HELP!

Only the "flash to pass" portion of the headlights are on the purple circuit. The main lights are on the brown circuit, and are not fused.

If you are blowing the red/green - red fuse, then you have a short somewhere on one of the red wires. That's going to be a bit difficult to find, but I would start by looking at the red wires where they attach to the various lights. Trace the red wires as far back into the harness as you can, hoping that the fault will be visible. If not, you'll have to uncover the wires as they travel through the car.

A couple of tips: disconnect the multipin connector located near the floor by the driver's footwell. This will disconnect all the wiring to the rear of the car. If the problem goes away, then the short is in the back of the car. If not, then the problem is either in the front or under the dash. Nest, disconnect the red wire from the dash light dimmer and see what happens. If the problem goes away, then the dash lights are the problem.

If the problem isn't solved yet, then the problem is in the lighting to the front of the car.

Don't waste your time looking for ground problems, as that isn't the cause of your troubles, although cleaning up grounds in general isn't a bad idea.
 
Re: '74 TR6 Fuse Box HELP!

[ QUOTE ]
Only the "flash to pass" portion of the headlights are on the purple circuit. The main lights are on the brown circuit, and are not fused.

[/ QUOTE ]

Oops. My bad. Best practice reading circuit diagrams before I start installing Dan's powerblock /ubbthreads/images/graemlins/crazy.gif

Mark
 
Re: '74 TR6 Fuse Box HELP!

Danmas, this seems like very good info. I truely appreciate you taking the time to help me out.

I think I could have possibly given one of the red circuit wires to much of a tug when I was switching out the box, thereby causing this potential short. I'll run down that length and see what I find.

I recently cleaned up all my grounds (thats what got all my lights working in the first place), so I thought it would be a good preventive measure to replace the box too.

Whodathunkit would have given me this?

Thanks again, see you down the road.

Cheers,

Steve
 
Re: '74 TR6 Fuse Box HELP!

Anything new to report? Are the lights fixed at this point and what did you find?
 
Re: '74 TR6 Fuse Box HELP!

Nothing new to report. I'm not gonna tinker with it any further, instead I'll take it to my local Brit shop for a repair.

I'm a total n00b with electrical stuff and after surveying the harness and the end point for the various lights, I couldn't find anything particularly obvious as a problem.

I look at it this way, I got a free soft top here y'day, which I did need but had way low on my list of priorities.
So I am most likely even, if not ahead a bit, right? /ubbthreads/images/graemlins/crazyeyes.gif
 
Re: '74 TR6 Fuse Box HELP!

[ QUOTE ]
I'll take it to my local Brit shop for a repair.



[/ QUOTE ]

What makes me a little nervous, your local "Brit" sold you Buss fuses for your new fuse box. Hmmmm.
I still think you should follow Dan's guidance and try tracing the problem yourself. You will learn a lot that way.

Why pay 80 bucks an hour for something that you need to know anyway. The sense of accomplishment is worth a bunch.

But, that is just me. I guess that I have been screwed by so many specialty foreign car and British car shops so often that I stay away from them now.

That said, perhaps I shouldn't be so judgmental of your mechanic. Maybe he is a good guy and might well help. I am just gun shy.
 
Back
Top