Problems with heating & defrost controls

[BoringLumina]

1995 Lumina 3100 V6, 191k miles. HVAC Blower only works on High, took HVAC control panel appart and all looks good and the switch checks out electrically. All fuses are good also, any ideas?

In addition but related I can not run the rear window defroster even though I hear the contactor clicking in the HVAC control panel. All fuses are good but no juice is flowing.

Again any ideas would be appreciated.

[Rhedalert]

more than likely either the fan blower resistor assembly is shot (more than likely), a bad relay (possibly) or the climate controller unit.

The resistor assembly is under the dash, bolted next to the fan. Passenger side of the dash, gotta lay on the floor (I usually take the seat out) follow the wiring to it, it's basically up against the firewall.

[BoringLumina]

Thanks Rhedalert, is there anyway to check that resistor assembly before pulling the seat and all that? In addition would that give me the problems with my rear window defroster? I noticed that the red and black lines which are a big gauge wire go through the same switch as the fan speed, that seems weird.

[Rhedalert]

No, it wouldn't have anything to do with the rear defroster. Now that you mention that, it seems more likely that the controller unit went bad. I'll see if I can find some troubleshooting/wire diagrams for that car (should be in my '95 book)

[BoringLumina]

Rhedalert,

I forgot to mention that up untill the begining of the month I had control over where the air goes, ie floor, dash, defrost. Now the HVAC is stuck on defrost, however I can still choose between hot, mix or cold. Does any of that make sense?

Thanks

[Rhedalert]

Rhedalert,

I forgot to mention that up untill the begining of the month I had control over where the air goes, ie floor, dash, defrost. Now the HVAC is stuck on defrost, however I can still choose between hot, mix or cold. Does any of that make sense?

Thanks

The switching between vent outlets is vacuum controlled. Usually the vacuum line coming from the engine gets broken, OR the line coming from the vacuum resevoir (black ball looking thing under the drivers side of the bumper/fender) gets broken (usually by the battery as it runs that way) has anyone done any maintenance to the car at the time you lost the ability to control the vent outlets?

[BoringLumina]

Rhedalert

Yep, I unplugged the vaccum line in the search for my vaccum leak and forgot to re-attach. Everything is working OK now, except fan speed. Will I have to pull much down from the dash to get at the resistor pack? Any idea how much that will run me? Thanks for your help.