Headlamp relay makes my cluster reboot.

[Janos Szav]

Hi Everyone,

I have a 2001 Chrysler Neon that is basicly the same as the Dodge Neon over there. It’s the earlier model so it has the 31th tranny and the car has less electronic in it than the never ones. Still I have some electrical issues. Because of these cars are well known from their headlamp switch connector melting issues I decided to use relays for the headlamps. I use relays only for the low beams. One for each side. I went safe and I didn’t wanted to overload anything even if I use 40A relays. The power comes directly from the battery through a fuse. The negative is also comes directly from the battery. The relay is switched by the cable that comes from the headlight switch. But the problem is that everytime I turn off the low beams my instrument cluster act like it reboots itself. I mean all of the warning lights comes up even the chimes comes up again, basicly it’s the same as I just start the car. Sometimes even the odo milage counter is go back a few miles. It happenes when I drive the car and switch off the lights. It is always go back exactly to zero on the last digit. The same thing happens when I turn on my high beams. So it happens everytime the relays are turning off. There’s only one exception. When the driver door is open. In this case everything works just fine. So I thought it has something to do with the ground cables. So I cleaned all of them. Nothing changed. I moved the ground of the relays from the battery to the headlamps ground. Nothing changed. I replace both of the relays. No changes. I also tried to build up the whole circuit from the top but using only one relay. Nothing changed. I even tried to use another battery. It doesn’t help. I renewed my alternator (I did it because of another reason) but still nothing changed. By the way the engine doesn’t have to run for the cluster to act wierd. Anyway I also tried to thorn apart the whole multifunctional switch and cleaned all of the coppers inside it but it doesn’t help. After that I thought it is something else and it has nothing to do with my “headlamp upgrade” so to rule this out I went back to factory. Well in that case everything works just fine. After that I tried just to control a relay with the headlamp swith without any bulb or anything on it. Well the instrument cluster “reboot” came back again. So I got to the point where I don’t know what to do 🙂 I think when the relay turns off some voltage appears on the ground. Otherwise why would it bother the instrument cluster. I forgot to mention that besides the clusters all of the dash and iterior light are go off for a second. The hadlamps or the back up lamps are working continuisly. So please help me to solve this mystery 🙂 I can’t believe that anyone can modify their hadlamps using relays except me.
Thanks for your help and suggestions in advance,
Jani

Topic

[Ty]

Being that the body control module aka the bcm controls the instrument cluster i think you’ve created some type of anomaly between the two by cutting out something it still trying to control.

[Janos Szav]

I cut the wires at the headlamp connectors so basicly those are the ones that switch the relay itself. But that is a great suggestion so I definitely will check a diagram that contains the bcm as well. Thanks!

[Author]

Replies