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Cadillac Repair/85 Seville heater blower

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Expert: - 11/7/2010


Question
I want to bypass the automatic fan controls (blower does not work any more) and install a 3 speed fan switch on the dash so my son can use the car.  The heater works, just not the blower.
Is this possible? How?
Thank you...We love the car.

Answer
Hello,

I am very familiar with this problem and yes I have seen the solution, however you cannot run a three speed switch. The best you can do is high and off.

Speeds are controlled by resistors and I am not aware of any switch made that will safely perform what you are attempting to do.

In fact, I would recommend running an in line fuse with no more than a 20 amp fuse in your switched power lead. Use 10 gauge wire and instead of using the factory heater wire, go to the ignition switch wiring under the dash and see if you can go off of ignition 2 for power.

It is a pain in the butt, but the potenial for a dead battery or fire is much lower.

I have heard of too many bypass jobs causing 12 gauge wiring to melt and the switch to burn up and that is why I give you the recommendations I do.

I don't know right off hand the exact specs on the bloer, but the amperage is quite high and that is why I want you to fuse it.


If you have issues, contact me at robo14@aol.com but you shouldn't.

Good luck!

Having owned over 20 Cadillacs and repairing thousands of others, I have found certain problems that are consistent among them.

1) heater blower resistor module which is non-servicable which causes the blower not to work, or run constantly even with the ignition off causing the battery to go dead.

2) on 1988 Seville/Eldorado and 1990 to 1999 Devilles, broken wires in their so called anti-theft systems, causing engine not to start.

3) if you run one of their aluminum engines from 1982 including the 4.1,4.5, 4.9 and north star above 230 degrees, it self destructs while it is running. There is No margin of error! If it runs above 230 f., repair or replacement costs will go from $1,000 to $5,000.


Http://www.autotheft expert.org






Http://www.autotheftexpert.com

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Rob Painter

Expertise

Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?

Experience

Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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