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Blower resistor

5 blower resistor went bust in the last 8 months, 1 original and 4 new. What could cause it?

How old is your Venture?

I know, it seems like a silly question, but it might make a difference.

I’m going to suggest that maybe the blower motor is bad, but that’s without knowing how old your Venture is.

Who’s replacing the resistors? Has anyone tested the blower motor?

A bad blower motor drawing too many amps would be my first guess.

Is there a way to check the motor out?

The easiest test is to spin the squirrel cage, if it does not spin easily you may have a problem.

There is no easy way - I’ve tried. You need to be able to measure the amps that it draws, so you need a testing device capable of that. There is a way to do it with a standard voltmeter - you can actually find instructional videos on Youtube.

At the very least you can pull the thing out and make sure it isn’t all gunked up & full of rodent nests and pine needles & stuff. You might also call around to see whether anyplace in your area can test its power draw if you brought it to them.

It spins easily. Do not feel undue resistance. But I agree that the blower itself is the most likely culprit.

the van is 10yr old. have not tested the motor - do not know how (it seems to spin properly). I replaced the resistor all 4 times.

The blower and the duct are very clean. I’ll take the motor to auto part shops. May be they have a way.

Can you even find the spec. for maximum amperage allowed. For current draw that will go above 1 amp (and you can bet this motor will) I use my cheapo 29.00 multi-meter instead of my 300.00 Fluke 87 that is rated for 10 amps. Before I get into telling you how to measure the current draw,see if you can find the maximun allowed. Have you inspected the pig-tail connector to the resistor pack? some GM trucks are having pig-tail issues and people are replacing the connector.

Chances are you have a blower motor drawing too much current (too many amps) through your resistor.

But you could also have a poor connection somewhere that gets disturbed whenever you replace the resistor, making it seem as though the resistor is at fault when in fact it’s a wiring issue.

Thoroughly inspect all wiring connectors for signs of heat damage, then replace the resistor and motor. The motors are inexpensive, and the only way to conclusively test it as good or bad is in the car.

If a motor spins easily it still does not rule out a broken wire that is shorting to the frame of the motor. The motor could work properly and still have a short. Most heater motors won’t cost more tan $60. Even if you have an expensive one, it might be worth changing.

The current draw in amps needs to be measured with an ammeter as a dragging blower is generally what kills a resistor to begin with, much less 5 of them.

Spinning easily does not mean that much. A couple of years ago the blower in my old Lincoln got where it would balk and become inoperative on rare occasions and this usually points to a faulty blower motor. It also spun easily but when the fan switch was turned to the HIGH position the intial current surge was about 25 amps with a steady load of around 15.

In the case of the Lincolns they do not use a resistor but instead use a blower module. Instead of a burned resistor what happens is that the module wire connector will burn.
Resistor or module, the cause is usually the blower.

The consensus points to the motor. It needs to be changed. Should a smaller fuse be used for future protection?

If you go to a smaller fuse, you will probably replace them often. I’d just use the Fuse tha Chevrolet recommends.