Chrysler Repair/93 LeBaron headlights stuck on high beam.
QUESTION: Hi Roland,
I seem to have run out of follow-up options, so wonder if you can consider this as the same issue from yesterday.
I've done no more testing yet, but overnight was thinking about this OPT-HORN theory and wonder if you would bear with me again.
It came to me the headlight flasher (OPT-HORN) is functioning correctly... pull the turn stalk and the high beam comes on, release the turn stalk and they go off, so that makes me think that the O-H switch has not gone closed circuit, does that sound logical?
The problem is when the headlight switch (on the turn stalk) is in the 'high' beam position, then the high beams do not go off when the main light switch (on top of the cowl) is turned off, the low beam lights function as they should, extinguishing when the main (cowl) switch is turned off. Also the high/low switch and relays must be functioning because the lights are switching between high and low beams correctly!.
I can't really see the logic behind what is causing it.
ANSWER: Hi Ken,
Try switching the high and low beam relays in the relay box, just as a test to eliminate that possible cause. If nothing changes then those are not the issue.
The headlight switch is the other suspect and IF there were a short circuit between one of the two poles of the main on-off section, when the switch is in the "off" position, and pin 3 of the switch (which is the high beam relay grounding wire attachment point) then that would explain why it is behaving this way. Check that out with an ohmmeter or continuity tester.
The only other possibility was the optical horn section which appears to function properly when the main switch is 'on' so presumably it functions properly when the switch is "off" (which you also might try to verify with an ohmmeter).
This sort internal short could well be the cause, but of course the circuit diagram doesn't show the actual physical details of the internal layout of the switch so we can't imagine how it could be so.
Feel free to do another rating and nomination if this proves helpful to you.
PS Another possibility is that the short is internal between pin 3 and pin 5 (which is attached to both the main switch and the 'parking switch' which I don't understand its purpose) and this 'parking switch' is shorted to ground when the main switch is off.
---------- FOLLOW-UP ----------
QUESTION: Thanks again Roland, you point to things for me to try over the weekend.
Yes, EVERY thing else appears to be functioning correctly, the O-H functions with the main switch either on or off. Ignition position makes no difference... which I don't beleive is should anyway. In fact the car is usable in the current state (as long as I don't leave it parked up with the headlights switched to high beam!), but its just knowing that there is something wrong!!!
I've looked inside the high/low/turn switch and its pretty simple... two shorting prongs move across a pcb to close the circuits and the high/low just moved a plastic block, again with a couple of shorting prongs, which is locked into place on the first pull of the switch and released on the second pull. The only complex part I can see is (what I assume is (could be wrong)) the load resitor circuit for the timed turn signals, but even this is just a two wire connection.
I was also wondering if any of these lights go through the body computer, but I can't seem to see a link, but then again the car does have the headlight (high or low beam) time delay if the lights are turned off after the ignition is turned off, so at a pure guess perhaps the body computer does play some role!
If its ok with you, I'll let you know if I find anything.
Ratings glady done, thanks for your help.
ANSWER: Hi Ken,
Mentioning the time delay when the headlights are turned off after the ignition is turned off is indeed likely a body computer function and may be the explanation. The high bear relay actuation coil grounding wire is not only connected to the headlamp switch but also to the body computer (as is the low bear relay on a different wire, both of which are shown on the lamp relay wiring diagram). So it is possible that the body computer time delay is not working as it should. Have you tried turning off the headlamps before turning off the ignition to see is that solves the problem? So that is another explanation as to why the high beams stay on.
Thanks for the ratings/nominations.
---------- FOLLOW-UP ----------
QUESTION: Hi again Roland,
Yes, I've tried all combinations of ignition/light switches on/off. If the car is just sitting there (not running, no ignition), I switch on to high beam... WITHOUT the main switch or parking switch on and the high beams come on and stay on!.
I've just done the first suggestion and swapped the relays... no difference :(. I'll have another plough through the wiring diagrams and see if I can find (and perhaps isolate, for a test) any ground that the body computer is delivering to the relays, but its dark here now (in Spain), so its a tomorrow job.
Have a good weekend.
The high beam should not come on, if you don't have the headlamp switch 'on', when you select high beam unless there is a short of the high beam switch to the optical horn switch's ground wire or somehow the body computer is doing the delayed "off" routine falsely and just holding it in that position. As the high/low switch is supposed to be wired it should not be connected to ground unless the headlamp switch itself were turned 'on'.
I would unplug the headlamp switch, then measure between pin 3 and pin 13 (the grounding pin) and see what happens when try low and high beam positions and also the optical horn positions. The latter should connect pin 3 to ground (13) but the former should not in either the high or low choice. It is either an internal short in the headlamp switch or if not then a malfunction of the body computer delay function grounding the high beam relay when it shouldn't.
Thanks once more for the rating/nomination.