Turn signel problem

[DanEC]

I thought I might as well start a fresh thread on this one. My passenger side turn signals have not been working. I used Bob's Electrical Primer troubleshooting instructions and found that the leads on the pass rear tailight were reversed. Changing those around got the rear turn signal working but not the front. At the front I changed the leads back and forth, and tried a different bulb wiithout success.

I then went back to the steering column and switched the wires to change sides. The Driver side front turn signal continued to work but the Pass side still did not work.

Then by trial and error I determined the green wire on the Pass front parking light is the power for the turn signal filiment and I traced it through the diagrams back to under the dash. As a test I hooked up a test light and stabbed both sides of the fuse holder under the steering column with the green wire and the turn signals on. The light in the dash was flashing but my test light never flashed. I then put the turn signals on for the Driver side and the test light flashed with the turn signals. The fuses look fine and there doesn't seem to be power to either side.

Apparently I'm not getting power to that fuse holder and I suspect that it comes from the turn signal switch (haven't traced that out on the wiring diagrahm yet.

I'm suspecting the turn signal switch. Thoughts? Suggestions for further testing.

Dan

[strictlypersonl]

Originally Posted by DanEC

I thought I might as well start a fresh thread on this one. My passenger side turn signals have not been working. I used Bob's Electrical Primer troubleshooting instructions and found that the leads on the pass rear tailight were reversed. Changing those around got the rear turn signal working but not the front. At the front I changed the leads back and forth, and tried a different bulb wiithout success.

I then went back to the steering column and switched the wires to change sides. The Driver side front turn signal continued to work but the Pass side still did not work.

Then by trial and error I determined the green wire on the Pass front parking light is the power for the turn signal filiment and I traced it through the diagrams back to under the dash. As a test I hooked up a test light and stabbed both sides of the fuse holder under the steering column with the green wire and the turn signals on. The light in the dash was flashing but my test light never flashed. I then put the turn signals on for the Driver side and the test light flashed with the turn signals. The fuses look fine and there doesn't seem to be power to either side.

Apparently I'm not getting power to that fuse holder and I suspect that it comes from the turn signal switch (haven't traced that out on the wiring diagrahm yet.

I'm suspecting the turn signal switch. Thoughts? Suggestions for further testing.

Dan

If the rear signals work, it's not the signal switch.
The fuses under the dash are strictly for the rear lights. They are there because the trailer relay is really sensitive to a momentary short, and some people were accidentally blowing it up when testing connections.

So...
First, check the several multi-pin connections from the trailer relay board to the dash harness. Sometimes a pin isn't all the way in. Pay special attention to the green wire connections.

If OK:
Turn the parking lights on. (Ignition off)
Is the passenger's side parking light on? Is it the same brightness as the driver's side?
If so, disconnect the green and red wire on the right front parking light. (The red wire is still live.)
Touch the live red harness wire to the each of the leads from the parking light. What happens?

[DanEC]

OK - I'll try in the morning. Both front parking lights come on with the switch on and the key off. The front lights appear of equal brightness. The red wire is lighting the parking light filiment. I'll try jumping it to the green parking light lead (turn signal I presume) and see what happens.

I can't see what difference it makes but this is the light that did not have a housing ground in the harness. I made a ground and jumpered it over to the other parking light to ground it.

And I'll crawl back under the dash to check the harness connections that the green wire runs through.

thanks Bob

[strictlypersonl]

If the ground isn't working properly, the parking light current will backfeed through the signal filament circuit and allow the parking light filament to work somewhat. Because the signal filament takes much more current, that filament won't backfeed enough current to light.

[DanEC]

Bob - I took most of the underdash harness connections apart and examined them closely (especially the green wire) and could not find any problems. Everything looked fully seated properly.

With parkiing lights on and key in on position (my flashers don't work on either side with the key off) I took the parking light lenses off and verified the dim filiment on both sides was lighted.

I then took the wires loose on the right parking light and jumped the red lead to the green light wire connection. The signal light filiment lit up and is brighter than the parking light filiment. I put another jumper wire on the housing to the frame for a second ground and that didn't make any difference.

With the Park lights on, key on, and flashers on the right turned on, I probed both sides of the green wire connection with a test light at harness plug 27/54 and got a flashing test light on both sides. So the signal is getting through that connection.

However, I notice that when I look at the connector schematic on page 21 of the wiring instructions, my wire identification does not seem to match. The schematic shows a purple wire for the right signal light instead of green??? It correctly shows yellow for the left side.

The wire schematic seems to reflect a straight shot from connection 27 to the signal light but I'm not sure that is a correct assumption.

Where to from here?

Thanks

[strictlypersonl]

The right signal light wire should be green. Neither my wiring instructions (for 780-on chassis) nor my wiring diagram show it as purple or violet. Go to the owner's section to download the appropriate diagram and instructions.
Did you check the pin contact locations on page 18 of the wiring instructions? Maybe the contact plate is reversed.

[DanEC]

OK - I see there was an update at car #780. I had the prior instructions. Let me see what has changed.

[DanEC]

Bob - I hate to belabor the point because I don't think it affects my problem, but I find the same reference to a pink wire for the right signal light in the 780+ wiring instructions for connection 27/54. it's position no 7 in the chart.

I checked my right turn signal with the details on top of page 18. It's se up exactly as shown - the shallow pin is at the top and the green wire terminal is at the 10 oclock position. I have the one staggered pin bulbs installed.

[strictlypersonl]

I'll have to check whether that diagram is incorrect on Monday. The only relevant thing though, is that the colors match on either side of the connection.

[DanEC]

Bob - shouldn't that be a straight shot on the green wire from the 27/54 connector to the parking light signal? I have a flashing signal through it. Isn't about the only thing left a broken wire or is there a fuse or another connection downstream of there?

Dan

[strictlypersonl]

Dan,
Have you used your test light at the parking light connections? Are you getting a signal there? Sorry if you answered this above, but my head is swimming...

[DanEC]

Originally Posted by strictlypersonl

Dan,
Have you used your test light at the parking light connections? Are you getting a signal there?

I'm pretty sure I have Bob - I rtried about every combination of connections up there I could think of. But after thinking some more about it I plan to try again. If I can pick up power with my test light by stabbing into the connector in plug 27/54 it seems like I should have power at the light unless there is some sort of discontinuity in the wire between the two. I think I will try switching parking lights from side to side also.

Am I right that is should just be straight wire from connector 27/54 to the light terminal - no other connections or fuses to run through?

If so, I'm going to take a length of wire and stab the wire strands into the back of the green wire connection in connector 27/54 and run it all the way up to the light and connect it to the light with a spade terminal. If that works then apparently there must be some problem with the wire in the harness or with the termination at the light.

If that turns out to be the case, I guess I will open up the harness in the engine bay and using my test light, stab the green wire through the insulation and try to find a signal. Then splice in a new wire and re-wrap the harness.

First - I'll try finding power at the light on the green wire at the parking light and switching lights.

[strictlypersonl]

Yes, it's an uninterrupted shot from 54 to the light. What bothers me most is the lack of a ground wire at 47. It's nearly impossible for me to forget that wire in the harness. That means that the harness may have been damaged between the box and the final installation.

[DanEC]

Bob - well this is just wierder and wierder.

I used my test light to get power from 27/54 and hooked a wire up directly to the light. The test light was flashing away up under the dash but nothing was happening with the turn signal. The back one is flashing. I did notice that the flasher, flashes a little slower when on the pass side than when on the operating driver side but when I put the test light on it and it is flashing, it speeds up to match the other side.

Next I switched bulbs from side to side - no change.

Then I unhooked the green wire and put my meter in the circuit to the light. I was getting 12 volts and it was fluctuating between 12.1 volts and 12 volts with the flasher. The filiment still not lighting.

Then I used my test light to get power from the yellow wire at 27/54 with the driver side flashers on. It flashed the same as the pass side.

Then I used my meter to check power on the pass green lead at the light with the turn signals off. I was getting a steady 12 volts.

Then I used my meter to check power on the driver side yellow lead at the light. I got 0 volts with the flashers off and 8 volts with the flashers on.

It seems like the green lead is getting backfed with power from someplace. Why the light filiment doesn't light up I can't understand. It seems it should be lit up all the time. Both filiments worked on the other side before I switched bulbs.

Maybe there are two problems - lack of continuity in the light and a short in the circuit??????

On the missing ground - it looks like the black ground wire is there but it runs uninterrupted from the headlight into the harness. It comes out of the lead from the headlight unit, runs exposed for about 3 inches and then goes into the wrapping for harness 51 that runs up around the radiator frame to the black wire at the 3 pigtails.

I could cut this wire and spice a leg down to the park light bezel if that would make any difference. Maybe the pass side light is getting backfed through the ground I ran to the driver side bezel.

I'm baffled - not having as much fun as assembling something.

Thanks

[DanEC]

Re: missing ground. There isn't any sign of damage - no cuts, splices, bare wires etc. Just insulated black wire running from headlamp to the wrapped harness. Only thing pecular is that it is short compared to the other two leads coming from the headlight.

[DanEC]

The mystery of the missing ground is resolved. I don't know how but the lug was shoved up inside the tubing from the headlight unit. When I was taking a picture it struck me that something was odd because the headlight unit was separate from the harness.

However, upon disconnecting the ground I installed and connecting the harness one, the problem with the flashers remained unchanged.

[DanEC]

Bob - any additional suggestions on what to check?

[strictlypersonl]

Switch the entire parking light assemblies from side to side.

[DanEC]

Well, I hoped I would have better news to report but alas that is not the case.

I removed both light units, checked them for same orientation of green and red wires with deep and shallow recesses in the sockets. They were opposite of each other so I switched the leads around on one so that they were exactly the same. When I installed them and turned on the parking lights one of them (driver side) was burning the signal filiment. So I pulled the bulb on that one out and switched the contacts 180 deg (back like they were) and reinstalled. The park lights were then burning on both. I tried the turn signals and the driver side again worked fine and the pass side did not work at the front - no change.

I pulled the bulbs and with the park lights on only (no signals on) I checked voltage at the contacts in the socket. I got 12 volts on the park light contact and 0 volts on the signal contact on the driver side. I went to the pass side and I get 12 volts on both contacts (???). I noticed this yesterday. Why I'm getting 12 volts on the signal contact and the bulb signal filiment doesn't light up probably has some electrical explanation but it's beyond me.

Next I went through connections Steering column to harness; connection 72 to 71; connection 70 to 74; and connection 27 to 54. I wrote down any inconsistencies I could find like in 70 to 74 a brown wire connects to a purple wire. On 72 to 71 there is a light purple wire in 72 for which there isn't any corresponding wire on the 71 side. Apparently this is used for the Triumph column. After checking everything with the connector schematics in the manual I could find no inconsistencies.

It appears that the turn signal wire at the pass parking light is getting backfed 12 volts from somewhere when the signals are not on.

It's also odd that the contacts have to be reversed from side to side - with the red wire as the parking light lead I would think they should be oriented the same on both sides. I think the green lead may be lighting the parking light filiment on the pass side - but I will have to check again to be 100% sure.

Dan

[DanEC]

My hunch that the Pass side parking light was getting power from the green wire appears to be wrong.

With ignition on, parking lights on, and signals off - I have 12 volts on both green and red contacts in the parking light socket on the Pass side. I can only pick up power on the green wire at connections 54/27 when the signal is switched on.

It kind of seems like the green wire at the Pass side turn signal is not the same green wire at the 54/27 and coming out of the steering column and at the split between rear and front circuits at connector 68. I guess tomorrow I will take my meter and see if I can get continuity on the green wire between 54 and the turn signal contact in the light housing.