Wacky Heater Problem

[Robert M]

I'm going to take a look at this mystery heater problem over the weekend.

 

Type: 87 GL wagon, A/C (no belt installed, not used), five speed with dual range 4WD.

 

What heater does now: Hit any button you want on the vertical control switch (except the AC button) and this is what happens - Mid-level heat comes on, no defrosters, no bottom heat. Out the bottom comes cold air instead of hot air.

 

Heater core does not leak. Heater fan only works in speed setting 3 or 4, nothing on 1 and 2 lower settings. :-\

[bheinen74]

tis the time of year for threads regarding heat.

what year model make?

[True2Blue]

tis the time of year for threads regarding heat.

what year model make?

 

Type: 87 GL wagon

 

 

Vacuum lines.... your welcome to bring it by sometime ill have a look at it with you

[GeneralDisorder]

You have a vacuum supply problem to the heater control system as well as a burnt resistor pack for the blower motor. Pretty simple fixes really .

 

GD

[Gloyale]

 

What heater does now: Hit any button you want on the vertical control switch (except the AC button) and this is what happens - Mid-level heat comes on, no defrosters, no bottom heat. Out the bottom comes cold air instead of hot air.

 

This means the vac line that goes to the controls in unhooked. Check the line in the engine bay that goes from intake to the reservior on the Pass. side strut tower. If that is good, follow the line across the back of the engine bay and over to near the Wiper motor. The line then goes through the rubber grommet and into the cab. If you can't find a break before that, then look up under the dash where the line comes in and make sure it's still connected up under there.

 

 

Heater core does not leak. Heater fan only works in speed setting 3 or 4, nothing on 1 and 2 lower settings. :-\

 

This is the resistor block that controls the fan speed gone out. Well, at least speeds 1 and 2 are gone (usual, the lowest settings are the first to go)

 

The block is located just after the fan in the ducting. Remove the lower panel on the passenger side, and look for a small rectangle block srcewed into the bottom of the duct.

 

It has 4 wires coming off it, variations of blue. 2 screws and one of the fan motor bolts come out to remove it. It can be replaced, or repaired with the right resistors. I believe there is a thread about repairing them in the USRM.

[Robert M]

Heater fixed, thanks to all the great advice. You guys are really just too good sometimes.