87 B2 blower fan resistor?

[87B2_4x4]

Last Friday, on my '87 B2, the AC blower motor was working fine on at least two speeds (I rarely use the high setting). Then on Saturday... nothing. The fan simply quit working. My research here led me to believe that the resistor went bad, is that what y'all think or should I look for something else. I did check the fuse panel and everything is good.

If it is the resistor, where do I find it? I seem to have misplaced my Haynes Manual while cleaning and rearranging my garage.

Thanks for your help.

 

[ab_slack]

Does the fan run when set to max? I don't believe that goes thru the resistor so if the fan runs it should just be the resistor. If the fan does not run at max there may be some other problem occurring such as the fan being bad or no power at all getting to it at all.

 

[JerryC]

It is on the passenger side under the hood near the blower motor but not right next to it. It goes into the airbox and sometimes the resistors get clogged up with leaves and then it burns up.

 

[87B2_4x4]

No fan when the AC is on Max. And I will have to go look for the resistor tomorrow in the daylight. It's interesting that the resistor would be in the airbox.

Thanks for your help.

 

[87B2_4x4]

I did a little testing this evening. I pulled the plug to the fan motor and tested for voltage. When the ignition is on and the fan speed selector is set to low, medium or high I get 12 volts; when it is off I get no voltage. And no matter what the fan is not moving or blowing any air.

My guess is that the fan motor died and not the resistor. What are your thoughts?

 

[JerryC]

I did a little testing this evening. I pulled the plug to the fan motor and tested for voltage. When the ignition is on and the fan speed selector is set to low, medium or high I get 12 volts; when it is off I get no voltage. And no matter what the fan is not moving or blowing any air.

My guess is that the fan motor died and not the resistor. What are your thoughts?

My electrical manual for 88 shows that the switch provides ground. The switch position selects what resistor to use for the fan speed. "High" bypasses the resistor pack, so it would seem to indicate that if the switch is on high and you have no blower you either have a bad switch or bad blower.

The resistor is cheap enough that I would (and I did) replace it with the blower motor. I think the resistor is in the airbox to help cool it.

 

[87B2_4x4]

Hmmmm. I may be sending my mechanic some work. This could take more time (and frustration) than I think it is worth unless someone has a good way to test either the switch or the blower motor.

I guess a couple of leads from the battery directly to the blower motor would test it.

 

[JerryC]

Yes. That should do it.

I paid to have mine done. I wish I had done it myself because while the blower was out I could have used a vacuum to suck out a bunch of dried leaves that eventually broke up and fell into the passenger foot well.

 

[87B2_4x4]

Well, I replaced my resistor and that didn't work. The old resistor had three intact coils and looked like a dirty version of what I got from the auto parts store. I also made two leads to wire the blower motor directly to the battery and it still didn't turn on. At this point I am not sure if I want to replace the blower motor or just take it so my mechanic. The blower motor is the last thing I can replace; the switch will have to be replaced by the mechanic.

 

[ab_slack]

Not surprised at your results here. As I said if fan didn't run when on hi it probably wasn't the resistor.

If you directly applied power to the fan and it didn't turn it probably is the fan. I never replaced one so don't know how difficult. I would be tempted to pull it, see how it turns manually (it may be obvious when turning by hand it is stiff). I don't know wha tth eodds are that it is just jammed tho or a little oil can get it going. Probably not for long even if it helps.

 

[JerryC]

The manual (wish I had bought that when I first got the truck, got it on ebay) shows the blower motor as easy to remove. Wiring connector, blower cooling tube and then three bolts.

Looks like the blower motor is cheap too.

 

[87B2_4x4]

The manual (wish I had bought that when I first got the truck, got it on ebay) shows the blower motor as easy to remove. Wiring connector, blower cooling tube and then three bolts.

Looks like the blower motor is cheap too.

Yeah. I had the air filter box off to replace the resistor and it didn't look too much harder to get the blower motor switched out.