Rear Defogger Electrical Problem
Thread Starter
Racer
Joined: Sep 2009
Posts: 463
Likes: 160
From: Port Birmingham AL
Rear Defogger Electrical Problem
The rear defogger on my 04 Z06 doesn't work. The relay "46" in the I/P Fusebox doesn't
energize, when turned on. The LED indicator on the defogger switch in the HVAC control lights up.
I have jumped the relay contacts in the relay socket, and the defogger heats up, correctly.
I have also shorted the "Rear Defog Relay Control" White wire #193 (Connector C2-Pin C3)
to Ground at the BCM, and the relay energizes, and the defogger heats up, correctly.
I am trying to determine if the problem is the BCM or the HVAC controller.
The HVAC controller send a "Signal" to the BCM "Secondary Rear Defog Switch Signal" on
purple wire #681 (Connector C2-Pin C10), telling the BCM to ground wire #193, and energize
the relay.
Does anyone know what the "Signal" voltage is, positive voltage or ground ???
I feel that the HVAC isn't sending this "Signal", but I need to know what it is, to measure it.
It could also be the BCM circuit not grounding the relay coil.
Thanks,
Larry
EDIT:::
AHH HELL!, The motor HAS to be RUNNING for it to work.
It's working, now, but wasn't earlier when i tore into it.
May still have problems in the future.
energize, when turned on. The LED indicator on the defogger switch in the HVAC control lights up.
I have jumped the relay contacts in the relay socket, and the defogger heats up, correctly.
I have also shorted the "Rear Defog Relay Control" White wire #193 (Connector C2-Pin C3)
to Ground at the BCM, and the relay energizes, and the defogger heats up, correctly.
I am trying to determine if the problem is the BCM or the HVAC controller.
The HVAC controller send a "Signal" to the BCM "Secondary Rear Defog Switch Signal" on
purple wire #681 (Connector C2-Pin C10), telling the BCM to ground wire #193, and energize
the relay.
Does anyone know what the "Signal" voltage is, positive voltage or ground ???
I feel that the HVAC isn't sending this "Signal", but I need to know what it is, to measure it.
It could also be the BCM circuit not grounding the relay coil.
Thanks,
Larry
EDIT:::
AHH HELL!, The motor HAS to be RUNNING for it to work.
It's working, now, but wasn't earlier when i tore into it.
May still have problems in the future.
Last edited by LWSZ06; Jan 10, 2013 at 04:12 PM. Reason: New Info!
