Cadillac Repair: 88 Cadillac Seville HVAC fan, cadillac seville, jumper wires

Question
Bill,

I just inherited a 1988 Cadillac Seville with 65,000 miles from a grandparent.  I'm planning to sell the car after cleaning it up a bit, so I don't want to put too many $$ into it.

The car has the digital climate control, but the blower does not run at all.  I've read on some of your posts that this is the blower control module and in some cases the blower motor.  Would this be a correct assessment in this case?  If so, where is the blower control module located?  How difficult is the blower motor to remove?  Is this done from inside the car or under the hood?

Thank you in advance for your advice!!

Chris

Answer
Hi Chris, With out further testing you are right in that those 2 parts are the most likely candidates. Both parts are located underhood up at the firewall in the same housing. The motor in the middle and the module on top passenger side.
If you remove the blower motor connectors and key on, hook up a voltmeter and command all the speeds. If it shows a differant voltage on every speed with the hi setting around battery voltage then the motor might be the only part needed. If on hi speed it is less that 4 volts you could have a bad ground or bad module.
Unplug the 4way connector at the module and test for 5volts on terminal B at the connector terminal with the motor commanded in hi. If less that 5 volts then the programmer or wiring is bad.
If you get 5 volts or more turn the key off and plug in the blower motor connectors and then useing heavy gage jumper wires(10-14)  from battery pos term...20A fuse...jumper wire with correct terminal on the end to fit the module terminal...module connector terminal A. If the fuse blows before 2 minuits then you need the motor and module. If it doesn't then and the motor runs with a normal sound then the book says the motor should be good and the module just needs replacing.

My recommendation is to replace the motor and module as a pair because the motor could have a bad spot and if it isn't replaced will cause the new module to fail in short order. The parts won't be cheap so if unsure of your diagnosis then maybe best to have a shop determine whats wrong and then you can replace the parts as they are easy to replace. Hope this makes sense and helps solve the blower problem. Bill