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Turn Signal Light Issue

PostPosted: 25 Sep 2009 15:16
by 123rmp
Hi,

I posted this before but by mistake put in the wrong part of the forum, so apologies, but putting it here in the "electrical" forum as well.

I've been a member for about a year but lurking, using the forum to help with questions, etc. Now I need to ask something.....

I've a 73 Challenger Rallye which I have cloned to be a 70. It's all coming together nicely. However, I bug is getting me. All of my lights and electrics seem to work fine except that the turn signals don't work properly.

The specifics are that they work fine when the running (park) lights are not on but when I turn on the running lights they behave differently.....the front one barely flashes and the other side sort of flashes but alternate to the other side. More or less it's the same on the back but just less pronounced. I have tried making sure theings are grounded but I would have thought a grounding issue would show up for the rest of the lights.

One additional item is that my dash and instrument cluster is removed and my amp meter wires are connected so the car has power.

Any and all ideas wold be most welcome.

Russell

PostPosted: 25 Sep 2009 15:36
by Goldenblack440
see my reply in that wrong section. Probably not very helpful though. Got a multimeter?

PostPosted: 25 Sep 2009 15:43
by 123rmp
Yes I do have a multimeter.

PostPosted: 25 Sep 2009 15:59
by 123rmp
Hi thanks for the reply!

- your answer in the other section was

"Is the turn signal relay clicking behind the dash? If not, then there shouldn't be anything at all at the indicators. Sounds like the symptoms for a blown bulb, but if its working a little...not sure. Not sure what you mean by "the other side". Does each light actually work for its correct side? Front and rear? Is what you are saying that they work for the correct side, but behave differently? Its quite possibel you have a 12 supply from the marker lights going to the indicators somehow, either fused from a melt or in the harness or firewall breakout somewhere. I can't help you for the rear indicators. Down here we have to have an orange (amber) flashing indicator, so the American cars with flashing brake lights, we have to rewire so that the reversing lights are used as indicators. We colour the lens orange or use orange bulbs, or if that is not possible we have to screw on horrible aftermarket lights somewhere."

Here are my answers....

Yes, it is working as the turn signals flash.....put a new flasher relay in today.

I have all new bulbs

Other side means...if I swith the indicator to left, the left side blinks but the right side (or OTHER SIDE) slightly blinks (maybe it just dims a little). Hard to tell. Works both ways right or left. But this happens only when the running lights are also on. It works normally otherwise.

I have all new harness so a melt or something is unlikely (not impossible) and would have immediately been noticed I think. I've got he whole dash apart so I can see all of that wiring pretty well...no smoke or melting smells detected anyway.

PostPosted: 25 Sep 2009 17:29
by moparteenchalleneger
sounds like a ground problem

PostPosted: 26 Sep 2009 12:43
by Goldenblack440
Electrical problems can give such weird symptoms. New harness and firewall plug should eliminate that other idea then. If they work normally with no marker lights, then that should be a clue. I assume its the same problem with headlights on as well? All the dash lights (inst flood illumination) come on with the marker lights so in the dark, have you had a look to see what they do when the indicators are flashing? With a healthy battery but engine off, you should notice a slight flicker of these lights because the current is rather high when flashing the lights.

If it was an earth problem i don't see why they would work normally without the markers on. You could also try getting two healthy batteries in parallel (still 12V, but able to better deliver over a load) and see if the symptoms stay the same or get better. If they get better, it is probably a poor connection somewhere that is causing a current drain. It is also possible the loom might be at fault. Use the multimeter on Ohms setting to do a continuity test at the two front indicator bulbs (between the L and R 12V centre connection). Do this with the marker lights off and then on. Might be a good idea to use alligator clips to hold the probes on the sockets and prop the multi meter up so you can see it from the driver seat when you switch on the lights. CHeck all earth connections too, the outside case of the bulb compared to the opposit side. Also try pulling out the rear bulbs (outer stop light?) and see what happens with just the front indicators. It could be a faulty loom connection at the back tail lights, if these are also used for indicators. Also too, try and find another high current user besides the marker lights, to see if its just associated with voltage use (eg foot on brake, or horn etc). Thats about all i can think of!

PostPosted: 27 Sep 2009 20:18
by 123rmp
It is fixed.

Issue was a series of things.

I tested the voltage at the rear and saw I was dropping 3-4 volts between the battery and the tail. So first I traced the voltage from front to back looking for th places where the voltage dropped. Cleaned the switch, the connectors, etc so that I was getting more voltage. That partially eliminated the issue. Then I put a really solid ground from the battery to the chasis as while the battery was grounded to the engine, I feared that the engine was not grounded as good as it miaybe should have been to the chasis. Then I put in a solid state electronic flashing module which will pass far more current.

Now it flashes like it should.

Thanks for the suggestions.

PostPosted: 28 Sep 2009 18:01
by Goldenblack440
Glad you fixed it. The Battery should always go the chassis (front rad support) as well as the engine. I assumed you had already done this if you had installed a new loom.