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Triumph TR6 - Lightless in Vancouver

I lost all lights on my 72 TR6, headlights, parking, dash and brake. Coincidentally it happened on the first day of rain in a long time - suspect a poor ground somewhere. Any suggestions on where to start looking first, is there a 'main' ground or will any ground from any light affect them all. Where do I look for the grounds?
Mike Strong

I had a similar experience while driving at dusk. All my rear lights and signals went out. I dismantled the entire rear light assembly and discovered that the bulb sockets are intended to ground by way of the assembly into the backing plates. I soldered ground wires into the bulb sockets and terminated on the body. That solved my problem. Can't say about the headlights - sorry.

John Parfitt
Calgary, Canada.
John Parfitt

I had the same problem with my '75. All that it needed is to take out the rocker switch, take it apart and clean the copper contacts inside the switch. Yes the switch can be rebuilt ie taken appart in pieces and cleaned up. Since then (3yrs) never had a problem since.
Steven

This mey seem too obvious but when I experienced a similar problem (lost turn signals also) it was simply a burned fuse. If you haven't, you might check that.
J.T. Cruz

I lost all of those lights earlier this year while driving at dusk. They flickered a few times then the fuse burned. The high beams still worked though, different circuit. After much searching and burned fuses, the culprit was a trunk light that just fell apart from age and one of the bulb contacts grounded on or near the fuel tank.
Wayne

Mike
Since you are a '72 year vehicle you do not have the rocker switch on the dash but instead the column switch. There is no "main ground" in the lighting circuit as ALL the lights are individually grounded. Obviously there is the main ground from battery to body and frame but if this was bad you would be thinking dead battery. With this in mind any one light with a bad ground WILL NOT " take out" the entire lighting system including dash lights. You will only have that one light out (assuming also it is not a bad bulb). So...you are NOT looking for a ground problem but instead a voltage loss problem. There is only one place that controls all your lights and that is...drum roll please...the MASTER light switch. If there is no voltage to that switch you will have ZERO lights ( the switch is NOT grounded). There is a possibility it is the switch itself but let us deal with the more likely first. So if we follow through the power supply side we have:
Battery + to/through the starter motor...to the Ammeter...to/through the ignition switch ( NW= brown/white wire)....to (NW colour wire to a connector to NU= brown/blue wire which is directly connected to the light switch. THIS connector is the first thing to check. It is located under the dash at the steering column where all the wires exit the steering column. Locate the connector with the wire colours NW one side of connector and NU the other side. With volt meter in hand take a voltage reading on the NW side of the connector (ignition switch does not need to be on). Do you have 12 Volts?? If you do then it is a strong posibility you have a dirty/bad connection here. Clean the 2 bullet connectors and with the light switch on in the parking light position touch the 2 together ( do not worry ..it is only 12 volts)...do the parking light come on?? If so the original snap connectors for bullet terminals are almost impossible to clean so replace it. It can not be AFTER the light switch because if it is that you lost the rear lights, front lights, and dash and at the same time lost the head lights and at the same time lost turn signals then if I where you I would rush out and buy a lottery ticket!!

At this point I will stop with the rest of the possible bad connection points. If this does not solve then post again and I will continue the story.

Remember...DIELECTRIC GREASE!!!
Good luck Mike.
Rick C
Rick Crawford

Rick C--You do know the electrics, so how about this problem. All tail/turn/marker lights work except only the left STOP lamp does not illuminate when the brakes are applied. The lamp filaments are good. What does that mean kimosabe?

Thanks.

Rick O.
Rick Orthen

Rick O
Oh...a brain teaser eh?
From the brake switch is a single wire (GP=green/purple) through the large molex connector (behind the driver side... side wall panel)to the left stop light/running light double element socket. Jumpered off of this socket is a GP wire to the right stop/running light socket. If the right stop light is working then you must have voltage to (at) the left stop light. If the running light is working in the left socket then the ground is OK. So what is left is 2 things....1. the bulb looks OK but is broken filament. OHM it out or replace the bulb with a brand new one to check...do not trust your eyes!!.....2 the bulb holder socket contact for the stop filament is dirty...or...not touching the bulb stop filament contact...or...a dirty spade connection (GP wire) on the bulb holder itself.
Since these bulb holders are repairable ( but you know this)it could also be the mysterious innner workings of the bulb holder itself. This is easy to check. Simply remove the right side unit and put it inplace of the left unit. Get a long stick and wedge it between the seat and brake pedal
or yell " honey...could you give me a hand for a moment please"....well... foot in this case.
If it is a bad socket you know you can fix it!
Now that was easy.....next.
Rick C
Rick Crawford

Ahah

The great Doctor of "Let there be light and Beep Beeps" jumps out to do battle with the evil Dr. Lucas once more. Dr. Lucas Prince of darkness and inventor of hand signals. You know the one people keep giving you just before you find out your brake lights/ turn signals have died again :)

Good job RickC. But I would be much more impressed not knowing you do battle with "32,000 DPI Geees" high tech digital electronics on a daily basis. So what did you do with the rest of your coffee break after last 2 replies :)

Bill


B Brayford

Rick- Now if only you could put some of that knowledge to your carb problem, you'd be "in like Flint"
Don K.
DON KELLY

Rick C--You're a Dan Masters! I'll do as you suggest and swap the tail lamp sockets. I studied my socket and it's a rather simple design that makes solid contact with the two pins on the lamp base. So unless there's a hidden break in one of the spaded leads, I don't see how I'm having this problem. I did the Nelson Reidel soldering on the ground strap, so I know that's good. Thanks again Rick!

Rick O.
Rick Orthen

Well, while we are talking about lights, I have had a problem with my hazard lights. Like they do barely blink (slow and dim), although everything else seems to work fine. Any thoughts?

I have been thinking about cleaning all the contacts for all the lights and smothering them with dielectric grease, but then I have heard that I am better off with out working hazards since having them on for an extended period could fry my wiring harness. Of course, I would rather fry my wiring than get creamed by an on coming car, but has anybody heard of this?

Ignatius "Nibbling at the endless TR6 to do list" Rigor
ignatius

Bill, it is Simple
I sent Mike and Rick O an invoice via e-mail.
Don, If only the carbs on a TR where as easy to diagnose as the electrics then yes, Flint and I would be siting in the back yard havin' a beer.
Rick O, well...I would not go quite that far. I do thank you for the compliment. Did you OHM out ( or swap out)the bulb? Mike and Rick, let us know what u come up with.
Dr. C
Rick Crawford

Igy
oops sorry meant Ignatius. How the heck are ya?
Comment first. Ignatius, can not recall year of your 6. Do you have the big pull knob flasher unit? Me thinks you do.
A little history lesson before I answer your question.
Before '72 the hazard warning light system had a toggle switch to a relay to a flasher unit. After '72 there is a pull switch ( relay inside) and a flasher unit. Will not get into the turn signal side as it is a different circuit and fuse. In all years the circuit is fused at 35 AMP. If we add up all our 4 21 Watt bulbs and invite Mr Ohm in on this he will tell us that we are dealing with 7 AMPS when all 4 bulbs are flashing. So both the flasher unit and relay see this current. On the wire side, it sees half this current (3.5)AMPS. At the molex connector (for the rear wiring harness) is is reduced further (one lamp..one wire) to 1.75 AMPS. Now we all want copper as our conductor as it has a very low resistivity factor ( .0134 OHMS/meter) better than gold not quite as good as silver but cheaper than both. This low number is good because there is a positive voltage drop across a resistor which represents energy lost by the current through the resistor. This lost energy is translated into heat. In this subjects situation...not good! Ok so enough of this mumbo-jumbo. To calculate a safe wire gauge for a given current one needs to know its length. I do not think I can talk Mr. Rigor into giving me this info so I will simply play it safe and say for a typical automotive application, conservatively speeking, 16 gauge wire can handle 20 AMPS.
So Ignatius, I do not think I would worry about a melt down of your wires. I do recommend to all to bypass the panel light rheostat (read resistor above). I would hazzard (sorry, no pun intended)a guess that your problem is the relay on the wheel arch drivers side. Go to your local auto supply, buy yourself a $2.00 flasher and put it in place. Is it faster? You do not want me to tell you that the next possible culprit is the switch!
Let us know Ignatius.
Rick C
Rick Crawford

Hi Rick C.,

Ya, I do have the pull type hazard, and I tried replacing the flasher relay, which got me to the current dim and slow state that I currently have. Please do not tell me it is the switch. If I remember right, this is not cheap.

Iggy
Ignatius

Ignatius
Yup...your memory is correct. Let me understand what you are saying. With a new flasher unit installed, it is slower and dimmer? If this is the case then maybe you have installed/purchased a heavy duty flasher. The type that is designed for heavier loads ie. a car or truck pulling a trailer...more lights.
Correct me if I am wrong but is your turn flasher unit and the hazard flasher unit not the same? A '71 flasher unit is three pin and your year looks to be only 2 pin ( like the turn flasher unit). If it is, try it out. Or possibly a lighter duty flasher unit. Unfortunately you will not find a nice rectangular one any more. I am not familiar with the pull type of hazzard switch. I presume it has an internal relay looking at the schematic. I am thinking your relay is not the problem for if it was you would have no flashers at all. Relays are not capable of only half working.
Good luck
Rick C
Rick Crawford

Thanks for your help, Rick. I am always amazed at the level of knowledge on this site. As luck would have it my lights came on before I did any work(I think the rain let up for a day). I cannot confirm the connections I cleaned were successful. Time will tell. Thanks again for your help.
Mike Strong

Hi Rick C, I couldn't help but notice your comprehensive understanding of the TR6 electrics. I would like to see if you can solve another small problem. All of my electrics seem to be working well except the ignition warning light. I've checked the wiring (with my limited knowledge; I believe it is connected through the ignition and the alternator) and the bulb is good. Any ideas? Thanks for sharing your knowledge. By the way, I can't remember if I told you that I did the carb rebuild and did a static timing. My 74 is (was, I mean, before the snow hit)running great. Thanks again. bv
B Vogan

Hi Bill

It is not so much that I have a comprehensive understanding of the electrical system. It is simply that I have schematics, know a little bit about what should happen in a circuit, and know how to diagnois it when not working. I am deffinitely not the only one on this BBS with this capability. I just happened to be the lucky one who started to reply to guys that could not see where they are going in the dark or use their horn instead of their finger to show disgust in another motorist who was surely wrong.

You are correct. The bulb is connected to the alternator via a brown yellow wire and to the ignition switch via a brown wire. The bulb holder is the ground path to the tach and the tach is connected to ground via a brown wire attached to the tach mounting clamp legs. Since you do not mention that the tach "night lights" or the oil pressure warning light do not work then I shall assume they do and that you have a good ground TO the tach. The alternator when it starts to output current will switch off current to the light and it goes out. You do not mention your alternator is not charging so again I assume it is. The light is simply an indicator if the alternator is outputing current or not. The ammeter basically does the same thing. Since the light should (under normal conditions) come on with ignition and engine started then go out there is a few possibilities.
1. most obvious, the bulb. As said before do not trust your eyes looking at a bulb and say the filament looks good. OHM it out!
2.Since the bulb socket is the ground make sure where it sits in its hole in the tach it is clean and rust free. DIELECTRIC GREASE!!!
3. The bulb socket. Good contact to the bulb...clean?? DIELECTRIC GREASE!!!
4. The B/Y wire to the alternator is a direct connection to the alternator....ohm this wire out directly to the bulb socket contact...should read virtually zero ohm (will only read the resistance of the wire).
I put my money on #2 assuming the bulb IS good.
Good luck...have fun...let me know what u find...and you are welcome.
Rick C


Glad to hear someones carbs are working fine!
Rick Crawford

Thanks Rick, I'll have a look. bv
B Vogan

This thread was discussed between 08/11/2002 and 19/11/2002

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