What should BCM Voltage be???
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
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From: Orange County CA
What should BCM Voltage be???
Does anyone know what the voltage from the BCM should be when it is triggering a relay? I would assume that it should be ~ 12 volts...but I am seeing ~10V.
Thanks,
Charley
Thanks,
Charley
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
All relay actuation voltage should be battery voltage. If the engine is running,,it should be alternator output voltage.
How are you reading the voltage? Make sure your using a good clean solid ground surface for the meter ground wire.
BC
How are you reading the voltage? Make sure your using a good clean solid ground surface for the meter ground wire.
BC
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
Thanks for the help.
Charley
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thanks Bill. The way I am reading the voltage is by removing the relay and then using a multi-meter to measure the voltage from the slot where the relay mounts and the actual ground point for that relay (specifically G202, which is a bolt to the frame near the passenger door). For the power to the switched side of the relay (the part that will be switched on by the actuation voltage) I read battery (or alternator voltage). When I measure the actuation voltage I am getting about 2 volts less.
Thanks for the help.
Charley
Thanks for the help.
Charley
BC
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
It is the relay for the Tonneau release. The schematic is on Page 12-5 of the 2008 Service manual. The issue is that when I try to lower the top, the tonneau cover starts to release but the latch does not fully release the tonneau. If I then release the switch commanding the roof to lower, the tonneau latch releases. I can then press the roof switch again and the top will fully lower. The interesting thing is that when the top is down and I am trying to raise the roof...the tonneau latch operates normally. The dealership has replaced all of the limit switches and the tonneau latch. In the process of checking all of the wires I found the issue stated above and I am trying to discern if it could be the cause.
I appreciate any recommendations you may have.
Charley
I appreciate any recommendations you may have.
Charley
Last edited by Charley Hoyt; Jul 13, 2010 at 09:50 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Do you have the CM7 top option??
What resistance reading do you get if you read the GROUND PIN in the relay socket to a good clean chassie ground??
If you want, I can send you the schematic
BC
BC
What resistance reading do you get if you read the GROUND PIN in the relay socket to a good clean chassie ground??
If you want, I can send you the schematic
BC
BC
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
I have a copy of the schematic....but, I could use a wire routing diagram to better trace the ground routing and the power wire routing so that I can check it for opens / grounds/ crimps, etc.
Charley
