Heater won't blow hard...

[tiger]

It's a 93 LWB.
The heater blower is spinning. I know. I stuck my finger in it. But only at low speed. When I put the heater selector switch on high, it the fan stays on low speed.
When I switch from heat to AC, the blower kicks in and blows like crazy. But cold air. Maybe that's a second blower motor? What gives?

[singingcamel]

its probably the resistor, located behind that little screen (passenger side). on the cowling..looks like a firecracker..marc

[tiger]

its probably the resistor, located behind that little screen (passenger side). on the cowling..looks like a firecracker..marc

But why will it blow hard when the AC is turned on? Are there two seperate blower fans?
Under the screen...you mean the three plastic screens on the OUTSIDE of the car?
If it were the resistor, I suppose that would affect only the lower speeds, not the high, no?

[singingcamel]

the resistor is behind the platic grill.
usually wil affect the higher speeds, thats what happened to mine.

[CJH]

Resistor drops the speed for the lower settings. Full blast is 12 volts directly to the motor. If one or more of the lower speeds is dead, the resistor is likely shot. A worn out blower motor will pull excessive amps & burn out the resistor (or it could have just died from age). From your symptoms, sounds like the switch might be faulty.

On AC a different fan is used (directly above passenger's feet).

[tiger]

Resistor drops the speed for the lower settings. Full blast is 12 volts directly to the motor. If one or more of the lower speeds is dead, the resistor is likely shot. A worn out blower motor will pull excessive amps & burn out the resistor (or it could have just died from age). From your symptoms, sounds like the switch might be faulty.

On AC a different fan is used (directly above passenger's feet).

That's what I figured, 12v and no resistor for full speed.
I don't know if it's the switch, because the switch does go to full blast for the AC function.
So there are two blower motors? Where is the heater one? The one above the passenger's feet is the AC only? That's the one I saw moving.

[Jerry 92RR]

Open the hood, remove a "grill" for air intake on the cowling. Look on the passenger's side and you will see the resistor pack. I have heard of people changing that our without removing the cowling. I would try that first.

You're a lucky guy (devilish sarcasm) if you get to change the blower motor. It's located inside the heater box containing many flaps, levers and fiddly crap. Not to mention the fun to be had removing it! Should you have to remove the heater box, replace the heater core while in there. Use an all metal replacement, not the metal / palstic combo.

Post up with progress, if you have to do the heater box, we'll provide a little "E"ssistance. -I will anyway.

[tiger]

Jeez. I remember having the squrrelcage on the heater fan slipping on the shaft on a 92 I had many years ago. I managed to get to it with an allen wrench without dissasembling the whole dash, that was lucky.

But...gee...I hope it's not the motor itself.
Tomorrow, I will try to jump around the resistor pack and see what happens. I still think the resistors should only affect the lower speeds.

I tend to doubt if it's the switch itself, as the AC blower works at all four speeds.

Anybody know where the wiring from the heater motor is routed? If I can supply 12 right to the heater blower, I can quickly diagnose the deal...

[tiger]

You know...if I can get to the resistor pack, in theory, I can run 12v right to the heater blower motor. After all, the resistor can only be in line with the heater blower and the switch.

[torque2]

Hey, did this issue ever get resolved??? I've got identical symptoms that started with some electrical smoke/smell coming out the central vents and VERY little air coming out on heat setting. It blasts full on HIGH ONLY w/ AC.
I replaced a very rusted out and deteriorating resister, but still get the smell.
Fortunately, the weather is getting warmer, but I'm fearing an ominous summer project, right? I'm guessing we're talking about a dying fan motor.
Did you end up replacing yours? Any useful tips? Feeding that resistor plug through the firewall was a bit of a pita!
Thanks,
Tim

[jgkmmoore]

heater motor speed, etc.

Take ALL Jerrys advice to the letter if you go into the heater box . You will understand why 'babbling insanity' is uphill of 'doing this job'. You MUST do the core at the same time...you WILL understand if you are 50% of the way done.
Good Luck.....hope you get an 'easy out'.
Jeff