M35 Shuts Down After I Turn Headlights On

[Tommy Kaira RL]

As title says In the last month after turning the car on to warm up and on 3 occasions when I turn the headlights on the whole car shuts down.

I then have to turn ign off and start again and its fine.

I have a 1 year old battery which I replaced with a bigger one. I dont think its a battery thing.

Has anyone else experienced this before?

[WAGON_BOY]

As title says In the last month after turning the car on to warm up and on 3 occasions when I turn the headlights on the whole car shuts down.

I then have to turn ign off and start again and its fine.

I have a 1 year old battery which I replaced with a bigger one. I dont think its a battery thing.

Has anyone else experienced this before?

never heard if it before........ something to consider even tho the likelyhood isnt great.

all M35's have an auto/park/low beam setup ?

if so could the auto selection be shorting out on something ie: you had foggies and they cut the wires and they are shorting out...... but this should blow the fuse not mess up the ECU.

also the power consumption of the headlights shouldnt have enough of a serge to make the car stall, but in saying that maybe a coilpack is playing up? (just another idea)

also check ur relays there could be a damaged one.

maybe an auto electrician can tell you more............. i usually play with 240V not 12V

cheers, Theo.

[Tommy Kaira RL]

i usually play with 240V not 12V

cheers, Theo.

I usually play with anything upto 275000V also. Yes your right I would blow a fuse if I had a short.

I dont think its a coil pack yet because its only shut down when the lights are turned on. But I am thinking something HV. I think the headlight transformers are breaking down to earth on the HV side and the ecu isnt liking it.

[zei20l]

so unplug the headlights at the headlight unit one at a time and test by turning the switch on.

see if it only does it with one etc. you appear to be a sparky, use your head

if it still stalls with both headlights unplugged, its somewhere in the switch or the loom.

when they automatically turn on, does it stall too? if not, its not the headlights, its probably the switch. i have a spare if you think thats what it is

[scotty nm35]

Sounds like a bad earth somewhere, I changed the battery terminals over to the larger ones for a better connection and fitted earthing wires around the engine bay, do you have an earthing kit? Check all the earth connections on the engine as they are known to corrode.

The BCM under the inside fusebox controls the headlight switches, I would think it then goes to the relay board behind the battery. Check all the plugs on that too.

[Tommy Kaira RL]

so unplug the headlights at the headlight unit one at a time and test by turning the switch on.

see if it only does it with one etc. you appear to be a sparky, use your head

if it still stalls with both headlights unplugged, its somewhere in the switch or the loom.

when they automatically turn on, does it stall too? if not, its not the headlights, its probably the switch. i have a spare if you think thats what it is

I smell what your cooking. The problem is it has only happened 3 times in the month I cant fault it when I try it again a few times. I hate finding intermittent faults. I will try leaving the lights on auto and see if it does the same thing over time.

Also it dosent just stall it goes completely dead all dash lights everything goes off and stays off until I turn ign off and on.

Its like a relay trips off and is reset when car is turned off.

[Tommy Kaira RL]

Sounds like a bad earth somewhere, I changed the battery terminals over to the larger ones for a better connection and fitted earthing wires around the engine bay, do you have an earthing kit? Check all the earth connections on the engine as they are known to corrode.

The BCM under the inside fusebox controls the headlight switches, I would think it then goes to the relay board behind the battery. Check all the plugs on that too.

Ive checked all the earths and yes I have an earthing kit around the engine bay that I made up. I think this has only started since the turbo rebuild. But I think the problem was there before I took the engine out.

I havent had any thing else play up yet but the problem is like if you unpluged the BCM and then nothing happens.

Ill have another look around that area and maybe ill unplug the ecu again.

[andy65b]

Brad, another thing to look at is your ignition barrel. I had a bad connection in the ignition barrel so that all the accessories would turn off at random times. Turned out to be a bad connection on the barrel so that if the key moved slightly power would be cut.

Cheers

Andy

[scotty nm35]

Ive checked all the earths and yes I have an earthing kit around the engine bay that I made up. I think this has only started since the turbo rebuild. But I think the problem was there before I took the engine out.

I havent had any thing else play up yet but the problem is like if you unpluged the BCM and then nothing happens.

Ill have another look around that area and maybe ill unplug the ecu again.

Engine out for a turbo swap? Who told you that was a good idea?