Cadillac Repair: climate control, Progressive auto theft SIU claims investigation EUO Denial expert, herb miller

Question
I have a 94 sls with only 112,000 miles. Recently the fan runs on low all the time, even with the ignition off. Every minute or so it speeds up a little and then goes back to low. It does not respond to the controls on dash. It will not  run at a higher speed. The A/c is cooling as pipes are frosty. Cannot find the relay that controls this. Checked all relays under fuse panel in engine compartment. Any suggestions would be appreciated.

Answer
Hello,

Here is the good news--Most likely not a relay! Bad news, one of 2 issues going on. Very common problem as far back as 1982. Isn't that nice? Cadillac did some pretty shabby things when it came to commonly known issues. They never attempted to rectify the issues-

1990-1999 The antiquated problematic VATS. That is what that big black ugly chip in your ignition key goes to. One of these days, the engine will not crank and it is because two tiny wires in the steering column break. Then if you go to the dealer, the latest rip off quote to replace ignition lock and keys was $700.00 Or, you can go to an alarm store and have that junk bypassed for around $50.00

The engine being made of aluminum since 1982 cannot be over heated even a little bit! Over heating is melting the engine and catastrophic damage will occur.

Then problems like yours, where the blower motor will run without the key and run the battery flat, or the motor will not work at all.
Depending on model and year many had a sealed electronic module for controlling blower speeds. Every one else used relays and resistors, but not Cadillac! The module is located under the hood on the passenger side of the firewall. If it is on your car, you can follow the blower wire up and you will see a module with three sets of wires running to it. It will have a cleared sealed bakelight on it. The only thing you can do is throw it out and attempt to see if you can find one new for about $300.00.
Other models just ran the blower speeds through the BCM (Body control module-A/K/A computer). In that case it's a bad BCM and needs to be replaced.

If it has a module you can bypass using an in-line fuse and running switched power to the blower motor. The down side is that you have either high fan or nothing with an installed toggle.

Good luck!

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