Questionhi,
i have a 2001 t&c and the headlights have been giving me trouble. first only one headlight would come at a time. by holding the multifunction switch on high beam, i could use both lights. after checking fuses and bulbs i took it to a shop and they said it was the Front Control Mod. anyway they did something to make it work but that lasted a week. I think they reset the BCM. later i got a used FCM put in and for a week the lights worked and then back to one at a time or working while holding the multifunction switch. so now six months later my lights wont work at all! a few days ago i banged on the passenger light and it came on but only for a few minutes. i even wiggled the fuse and relay box under the hood one day and one light came on but that didnt last either. What could be the problem? I'm thinking the switch or a wire? Every other light works including interior, parking, turn signal, etc. except the headlights. Where is the bcm and how do you reset it? At least this might help me for a few days at a time until i can get this solved. Thanks.
Answer
Hi Alisha,
With that complex history there are several possibilites. The one side only behavior would not be due to the bcm as that controls both side voltages simultaneously.
The one-sided problem has to be related to either poor connections at the fuses in the box that is under the hood, or a poor connection between the bulb socket's black wire and the place where it is attached to the body (for the return path of current back to the battery, located in the cabin at either the left or right front corner of the footwell where there is a multiwire common grounding point).
The both side no work problem could be the headlamp switch itself, the body computer, or the connection of the body computer to the low beam relay (or the relay itself) or from there to the fuses in the fuse box under the hood.
The only way to get to the bottom of this problem is with a voltmeter and a circuit diagram. You also could use a simple neon 12 volt test light to trace for the presence or absence of voltage at any given point. I would start with fuses 4,5,6,7, in the box under the hood. Those fuses feed the head lamps their voltages (one fuse for each filament). I would test the fuses to see if when you have the head lights on low and then on high beam settings, which of those fuses show voltage and which do not. Once that is determined we can go on further. You measure with the voltmeter or the bulb tester by placing one of its wires on the fuse of interest and the other on the - post clamp of the battery which is nearby (or if the lead is not long enough placed on any shiny structural body or engine surface to which it will reach). Make sure that you have the ignition switch in the "run" position (the engine doesn't have to be running however).
The bcm is under the dash attached to the rear side of the fuse box. It is not something that "resets". If you have had any history of water leaking from the windshield and dripping on the fuse bos/bcm unit that could well be the cause of the problem. We'll deal with that issue after you do the fuse measurements, if necessary. But tell me if you know of such a history.
Let me know the results by using the "thank/rate" tab below to get back to me, without having to wait for me to be available to take a new question. There is a space for comments to which I will reply.
Roland
NEW Question:
Hi Roland,
I couldnt use thank/rate form because i didnt see the button. i had a question and i didnt want you to forget the previous so i copied and pasted the previous. My next question is where are fuses 4,5,6,7 for the headlights? on my fuse box there are words and not numbers. Could there be another fuse box?
AnswerHi Alisha,
I hope everything works out with the headlight problem. Please let me know by using the 'thank/rate' tab below.
While you are there, if I might ask a favor: where it asks about a 'nomination for expert of the month' I would appreciate your entering a 'yes'. I am in a close race for that honor so every vote counts!
Roland
Hi Alisha,
The fuses for the lights are in the long narrow box next to the battery in the engine compartment. The fuse are in a long row on the side next to the battery. Count from the front of the box. 4,5,6,7 are 10,10,20,and 15 amp, respectively. Look closely at the wire inside each fuse to make sure that it isn't cracked, which could make it work/fail variably, as you described. I am basing this circuit/location upon my '98 factory manual and the '95-'00 Haynes manual which I assume applies to your '01.
There is another fuse box hidden under the dash to the left of the steering column which to access you remove about 7 bolts from the panel that is under the steering column and stretches to nearly the side panel (two on the left, two on the top middle, 3 on the right). But that is not the fuse box where the light fuses are located.
Roland
PS The thank/rate tab should be available now, you get one shot at it per original question. Thanks for putting in the history.
Hi Roland, I dont see these fuses under the hood because I think my car uses a 01-07 manual. Do you have that fuse box info? I dont understand what in the fuse box goes to my headlights. even on the diagram it says headlamp relay and there is no relay in that space and never has been. another thing, i went to test the headlight ground wire (the black one) right? any way there is some burnt, black color at the bulb socket on the passenger headlight like it had been burnt. i checked fuses with a test light and everything seems to work. i cut wire on the swithc (black and orange, not sure if its the right one) and i got no positive light from the test. I guess this might be for a mechanic? what do u suggest i check now? Should i just get a new switch? How can i tell if the switch is bad just by looking at it?
Hi Alisha,
While I don't have a manual newer than '99 I have to think that there is a power distribution box under the hood. Do you see the jump start + post, I think perhaps on the driver side strut tower at the outside corner of the compartment? There are 3 red wires located there. One comes from the hidden battery, one goes to the starter motor, and one goes the power distribution box. If you find that spot, follow the wires as you can and you may find the box with the fuses that I described. Please let me know.
Thank you very much for the reply and for the nomination. I hope we can solve this together.
Roland
