Chrysler Repair/Headlights won't turn off: '92 Lebaron convert
QUESTION: Hi Roland, thanks for sending out the info to disassemble the headlight pod...Here is where it stands now....I removed the pod and disconnected all wires leading to the switches...Low beam headlights are still on....Seems the only way I can turn off the headlights is to A) pull the 40 amp fuse under the hood.. B) Pull fuses 17 and 18 under the dash..or C)pull out the relay on the top row under the dash (second one from the empty top row spot) have tried switching it with other similar relays on the same row but lights still go on when plugged in...Since switching relays doesn't change anything can I rule out stuck relay?..Since I have disconnected headlamp switch and pod can I rule out the switch?...Anything else you can think of that I can check?
ANSWER: Hi John,
There is one other possibility which I can't fully know why until you check it out, but here goes:
The Body Control Module does have a wire also connected to low beam relay activation coil. The purpose of that, I believe, is to tell the Module that you have turned on the low beams so that it can then alert you if you leave the car with the lights "on". The alert is accomplished when it "sees" that you have grounded the activation coil via the headlamp switch "request" which is in fact a separate wire on pin 13 that goes through the headlamp switch to ground. Grounding that end of the relay activation coil is of course what turns on the relay. So my thought is that the separate wire from the relay to the body control module has some how become shorted to ground all the time due to a crack in the insulation or possibly the body control module has a fault internal, related to the wire (though that seems unlikely).
Let's check this out: remove the low beam relay and test the front-most pin of the socket (which may be labeled 13, maybe not labeled, but in any case the front pin that is closest to the parking lamp relay), and see whether it reads a dead short (0 ohms) to ground (any shiny metal chassis surface nearby). With the head lamp switch disconnected OR at least not requesting low beam head lamp if connected, that pin should not be grounded but rather should be 'floating', e.g. measuring something other than 0 ohms to ground which is the voltage of the input to the body control module. If you want verify that it is or is not a shorted wire to ground then go to the body control module (which is hidden behind the 'kick panel' just in front of the passenger-side door opening, near the floor). Remove the 'natural' color plug from the module which carries that wire from the relay on both pins 20 and 21, an orange/white wire. If the pin 13 at the relay is still showing a short to ground then the orange/white wire(s) is indeed falsely shorted to ground somewhere along its pathway. If it is not shorted to ground, then there is something wrong inside the body control module.
Please feel free to do another thank/rate and nomination. I hope we will solve this now.
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QUESTION: Wow, once again appreciate the quick response...I will do my best to check out the pins for this week...Might be tough as these replays are tucked way up under the dash and very difficult to reach...Also wanted to make a couple of side notes...1)when turning on and off the lo-beam headlight switch on the pod sometimes the headlight covers open and close and sometimes they stay open...fairly random...also 2) have noticed for some time before this not turning off issue that if the headlight switch was turned off before turning off the ignition switch the lights would go off, but if the ignition switch was turned off first then I would have to hit the headlight switch 3 times to have the lights turn off...is it possible that this was a precursor to the trouble I am having with the headlamps now?
ANSWER: Hi John,
Instead of testing at the relay, you could also go directly to the body control module as described (remove screw holding the cowl panel in place and the door opening scuff plate for access), remove the natural color plug and check whether or not the orange/white wires on pins 20 and 21 are grounded, and with the plug inserted back in module check the wires again by probing at the wire/plug socket interface with a pin or similar probe. The headlamp covers are controlled by the body control module (and probably rely on the orange/white wire to know) so if it were giving a false indication of the headlamp switch request for lamps or not, then that would similarly explain the problem. If the orange/white wire is not found to be grounded when you pull the natural color plug, then it may well be that the control module is falsely grounding the wires and that would similarly keep the doors open. The historical malfunctioning is of interest by I don't see it as explaining the present situation except to note it does suggest the body controller is involved.
If you do opt to test for a short in the orange/white wire that goes from the low beam relay actuation coil to the body control module by checking it out at the natural-color body control plug, then be sure nonetheless to remove the relay because the other end of the relay's coil is connected to the battery all the time so there will be voltage on the orange/white wire which will invalidate your test for whether the orange/white wire is shorted to ground or not.
If it is not shorted to ground but rather shows infinite resistance to ground then I would have to conclude that something is wrong with the circuit in the body control module (on pins 20 and 21) that 'senses' when you have grounded the wire by means of your requesting the headlamps to operate.
Also, the orange/white wire to the body control module serves the purpose of initiating the concealed headlamp relays in synchrony with the headlamp relays. So your observations about the covers mal-functioning is likely related to the same reason for the low-beam relay to not turn off.
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QUESTION: OK, here is what I have found upon further investigation...I found the body control module and removed the natural color plug..pins 20 and 21 show voltage (from the relay?)....when I pull the headlight relay the voltage on 20 and 21 disappears and no short to ground either..so I guess the orange/white wires have no short to grounds... Upon placing the relay back and leaving the natural color plug unattached the headlight switch works on and off but now the headlight covers don't work, prob due to the natural color plug being unpluged...so perhaps it is a malfunction in the control module keeping the headlights on....if so perhaps I can just cut one of the orange/white wires and plug the natural color plug back in have everything else work but the 'leaving the healights on alert feature'?...thinking that finding a replacement control module might be difficult and or pricey..
The orange/white wires do two things at the body control module, I believe. One is the headlamps 'on alert' and the other is to open/close the concealed headlamp covers via their three relays. I am not clear whether those covers stay open if you cut one of the wires and I am not clear as to which wire you would cut (the specific purpose of the 20 and 21 socket is not explained), but if so then if you can 'live' with open doors then it may be the solution for the headlamps not shutting off. I think you may be able to find a used body control module from a wrecking yard specifically from a '92 or '93 model, or possibly a new one from a dealer.
I am pleased that we are narrowing in on the issue.