taillight problems Topic is solved

[all2many]

Was not able to operate fogs and lic light also went out. Now do I replace ignition switch or whole key module ? That could run about $400. Guess I'll try switch first only like $60.

[abscate]

Just the ignition switch, electrical part - no need for the key part. But - do some diagnostics first - I would be surprised to find a key part knocking out ONLY those lights. It usually takes out a lot more.

[mrbrian200]

Found it. 3/1 (Ignition Switch), Pin 8 runs direct to the REM A29. No telling if there's a dedicated physical contact inside the ignition switch for this that could be 'lost' independent of everything else. Based on all2many's description/symptoms, it appears likely.

REM.JPG (82.75 KiB) Viewed 887 times

The diagram showing the tail lamps isn't complete in my opinion. If loss of this 12v signal from the ignition switch to the REM causes the tail/lic/fog lamp to fail, it needs to be on there.

[abscate]

Can you trace the ignition switch outputs diagram to help figure this out?

An ignition input to the REM could be as simple as the CANBUS version of an X-relay circuit - turning off electrical loads for cranking

[mrbrian200]

If it's reasonable weather tomorrow I'll probe the voltage behavior on A:29 at the REM at KP0/I/II/III. Temp dropped like a rock today, windy and no garage on the premises. With that probed information of a known working car he should at least be able to confirm whether or not this signal from the ignition switch is present/proper. If CANBUS data were corrupted preventing proper communication to the REM, it is likely that other systems would also be affected and he'd be seeing various warning lamps/messages on the DIM. He didn't mention anything of that nature when asked. Control of these lamps is quite likely a combination of CANBUS commands and this wire. He said they came back on when he wiggled the key. Now that I see that there is direct connection between the key switch to the REM I think it's fairly safe to say a problem with the ignition switch is likely. I agree, if it were my car/money I would probably figure something to double up the diagnosis before ordering a part.

Think Think Think.

All2many: Do you know how to probe the wire at A:29 on the REM? If, while engine running + lights not working, the voltage at A:29 changes when the lights come on while you wiggle the key then I think there's enough to make a a solid diagnosis: bad ignition switch. Could be 0v jumps to 14, or 14v drops to 0.

[mrbrian200]

Voltage at REM A:29 from the ignition switch.
KP0: 0V
KPI: 0V
KPII: Battery Voltage (12-14.7v)
KPIII 0V

If the lights came on after wiggling the key, this has to be it. There's no other direct/indirect connection to the REM controlled by the key switch which would not affect other systems.

[all2many]

Sometimes the taillights would remain on after shut down, fogs would not go on ,plate light was low dim. Did not investigate further seemed enough problems to look at. One thing at a time hope this cures VIDA fault as it is only one turning up.