az28

Can anyone tell me what functions are controled by the "body control module"
and where is it located on a '93 convertable? I have some quirky symptoms that a local mech. says may be caused by this part. Thanks
JR :confused:

az28

ttt please

JasonL

Controls just about everything except the engine/tranny... such as power windows, door locks, mirrors, alarm, interior lights, etc. On my '96 it's located behind the radio I think.

az28

Does anyone know procedure for changing one of these?
Thanks
JR :flag

hookedup

You'll find the CCM R&R in the factory service manual.

Dave :yesnod:

Tom Piper

The CCM (Central Control Module and sometimes called the BCM for Body Control Module) is the master computer (the ECM, EBCM, and C68 Climate Control modules are slaves).

The CCM is programmed with the VIN# and the option content of the vehicle. In addition to the "delayed accessory bus" and such, it also holds the current odometer reading of the vehicle.

The correct procedure to replace the CCM (as a previous post said, this procedure is in the shop manual) with a new or Delco refurbished one is to program it within about 100 miles (after 100 miles, you are permanently locked out) from the time it is put in with the VIN#, correct odometer reading of your vehicle, and the option content of your vehicle. This is accomplished with a Vetronix Tech-1A, or MasterTech scan-tool with the *****dealer supplied ONLY**** Mass Storage Cartridge. Vetronix will not supply the after-market buyers with the software to program the CCM. This is done to prevent odometer tampering. Since I have a Vetronix Tech-1A, I borrowed the Mass Storage Cartridge from a dealer to program my CCM when it went bad. I already had all the Vetronix cartridges that I could buy, but didn't have that capability.

If someone puts a CCM out of a lower mileage vehicle in the car, you can (with the Vetronix scan-tool and the Body cartridge) access the VIN# in the CCM to see if it belongs to that vehicle. Plus, the donor CCM would have to have the same option-content for them to work -- keep in mind, the CCM is the master computer.


Tom Piper


[Modified by Tom Piper, 8:27 AM 5/6/2003]

az28

Can these things be replaced with used ones? I bought one on ebay already.
Can I just plug it in and see if it fixes my AC prob.? or is that not possible?
Thanks!
Jay :flag


[Modified by az28, 3:28 AM 5/7/2003]

az28

ttt

-=Jeff=-

you could, assuming all the accessories are the same on the donor car it came from.

What is the AC doing that leads you to believe it is the CCM

az28

I have a problem with the fan shutting down and coming back on. Sometimes if I close the hood when the fan has shut down, it will start back up. I have had it shut down after hitting a bump in the road , or driving up or down a steep grade in the road. I have shut the passenger door and had it come back on. I replaced the fan relay, and checked for bad connections at the wire plugs. Everything looks ok. A mechanic suggested that the "body control module" could be bad. Any thoughts? Thanks!
Jay :flag

Tom Piper

I doubt that the CCM has anything to do with your coolant fans shutting down.
The coolant fans are controlled by the ECM -- the ECM uses the input from the coolant temperature sensor and AC high-side pressure sensor to determine when to turn on the coolant fans. On the LT1 engine, the coolant temperature sensor is in the water pump; the AC high-side pressure sensor is on the AC high-side pressure line by the dipstick.

Plus, if the ECM detects a serious problem and goes into limp-home-mode, the fans are enabled regardless of temperature or AC high-side pressure.

If you are talking about the heater and AC blower and you have the C68 Electronic Climate Control, that is controlled by the climate control system.
However, there is a blower resistor module that is in the air-handler next to the blower motor that would be a good check.

Plus, if the brushes in the blower motor are worn out, you could get those symptoms -- when the motor is jarred, the brushes make just enough contact to start. But, in the case of worn-out brushes, I would expect that once the motor started it would run until the blower is shut down by you and it wouldn't start the next time you started the car because the brushes are in a spot on the commutator that it they can't make electrical contact.

Tom Piper


[Modified by Tom Piper, 8:08 AM 5/7/2003]

az28

Thanks Tom,
I am speaking of the blower motor. I' check in to the "resister module"
today. If the brushes in the motor were bad, do you think it would still run at high speed (when it is running)? Thanks again for the help. I live in S. Fla and it's in the 90's already!
Jay :flag

Tom Piper

Normally, if the resistor module is bad, the blower will run high-speed only.

If the brushes in the blower motor are bad, the blower will probably run in all speeds once it is turning. However, once shut down, it may not start again until you jar the motor enough to cause the brushes to make momentary contact with the armature commutator. With bad brushes, once the motor is running the brushes will just bounce over the bad area and keep it running.

Tom Piper

az28

I have a new blower motor coming from Autozone tomorrow. For $40 I'll eliminate that possibility. It sounds like a good chance that is where the problem is. Thanks again! :flag