hvac blower speed
Thread Starter
Racer
Joined: Oct 2011
Posts: 395
Likes: 6
From: woodstock ga
hvac blower speed
i have an 89 with elec climate control. the blower speed does not seem to be very strong. i have removed the blower and cleaned the avap core (not much blockage ). i think that the blower module is bad. anybody know how to test or trouble shoot.
thanks in advance
thanks in advance
Racer
Joined: Sep 2007
Posts: 375
Likes: 18
From: Lawrenceville Georgia
Yea, at best the C68 climate control is half-*** in my opinon.
With that said, can you hear the fan motor change speed as you go from 01 to 10 on the control panel? If so, module "should" be OK.
Joel
With that said, can you hear the fan motor change speed as you go from 01 to 10 on the control panel? If so, module "should" be OK.
Joel
Thread Starter
Racer
Joined: Oct 2011
Posts: 395
Likes: 6
From: woodstock ga
the fan speed will change when i manually command. older GM veh had a tendency to lose the high speed blower switch. they would blow throughout the range except on high. i realize that this is a different system but i theorize that the principals are the same. it does blow some on the 10 setting, just doesnt seem to be that strong.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Jumper Blower directly to battery - if it's the same, your air may be going somewhere else. Ductwork is sealed with foam. Remove the Passenger Hush Panel and if you've got an air stream flowing pass the ECM towards the floor, the foam is shot. Remove the top Pad to reseal. Also feel below the Evaporator case, engine compartment, along the firewall. If the Evaporator has been replaced, this section is often left unsealed.
Input from the controls is the brown wire at the Module. 1 is about 2 volts; 10 about 6. Output is purple. At 1, the Module has boosted voltage to 4 volts, at 10 to 12 volts.
Check Blower Connector for voltage drop which would be indicated by discolored wiring. If there, remove weatherpak and solder the connectors to the wire.
Input from the controls is the brown wire at the Module. 1 is about 2 volts; 10 about 6. Output is purple. At 1, the Module has boosted voltage to 4 volts, at 10 to 12 volts.
Check Blower Connector for voltage drop which would be indicated by discolored wiring. If there, remove weatherpak and solder the connectors to the wire.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
the fan speed will change when i manually command. older GM veh had a tendency to lose the high speed blower switch. they would blow throughout the range except on high. i realize that this is a different system but i theorize that the principals are the same. it does blow some on the 10 setting, just doesnt seem to be that strong.
The C68 automatic climate control uses a control module to control the fan speed. It's got a huge heat sink and is mounted in the same position as the blower resistors of the old/manual system.
I have the C68 system and its blower fan air volume is way too low in my opinion. I don't know whether the ducts are too convoluted or the blower just doesn't have enough horsepower -- maybe both.
Burning Brakes
Joined: Mar 2010
Posts: 1,094
Likes: 68
From: Providence RI
I also feel that my C68 blower doesn't have enough juice. It seems when I first start the car, it blows more air than when everything gets hot. I also notice it blows more air when its on recirculate, but that is to be expected.
Settings 1-10 make minmal changes, but I cant really see a difference from 7-10 so to speak.
I have not looked at the posibility of leaks in the air ducts, but I am sure there are some. My ac blows somewhat cold, but I know I am missing seals around the EVAP housing such as where the tubes go into the housing. The Evap core has been replaced, but they hacked the top of the case off to switch it, rather than tear it down like they were supposed to. This makes me think they half assed it, and now I have to fix it right someday.
Any ideas?
Mike
Settings 1-10 make minmal changes, but I cant really see a difference from 7-10 so to speak.
I have not looked at the posibility of leaks in the air ducts, but I am sure there are some. My ac blows somewhat cold, but I know I am missing seals around the EVAP housing such as where the tubes go into the housing. The Evap core has been replaced, but they hacked the top of the case off to switch it, rather than tear it down like they were supposed to. This makes me think they half assed it, and now I have to fix it right someday.
Any ideas?
Mike
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
It's subjective, but to me they blew ok when built and still do when it's right.
Half-assed to hack up a case? Full-assed is more like it.
Check squirrel cage - some have found that it's broken.
If you have a clamp on, check draw - old motors can suck 25 amps, though they usually cook the wires at that amperage. Speaking of which, if you suspect a voltage drop, you could up the wire gage a notch (or substitute a fresh wire; ie, a brand new one, hopefully with less resistance). Experiment by jumpering from the Module to the Blower. Do not change the fuse.
Monitor alternator/battery. With extended idle, all accessories can exceed output so you end up on battery. Voltage drops, fan slows down. So does the radiator fan or fans and if you're intentionally running the Pusher/Aux (through '89), don't - there's not enough low rpm juice for it and the a/c. As you suck the life out of it, it will overheat. Working a/c should have coolant temps 8 to 10 degrees less than if it were off. Otherwise, you don't make cold air or get full blower.
Put on the solid top if you've got one.
Half-assed to hack up a case? Full-assed is more like it.
Check squirrel cage - some have found that it's broken.
If you have a clamp on, check draw - old motors can suck 25 amps, though they usually cook the wires at that amperage. Speaking of which, if you suspect a voltage drop, you could up the wire gage a notch (or substitute a fresh wire; ie, a brand new one, hopefully with less resistance). Experiment by jumpering from the Module to the Blower. Do not change the fuse.
Monitor alternator/battery. With extended idle, all accessories can exceed output so you end up on battery. Voltage drops, fan slows down. So does the radiator fan or fans and if you're intentionally running the Pusher/Aux (through '89), don't - there's not enough low rpm juice for it and the a/c. As you suck the life out of it, it will overheat. Working a/c should have coolant temps 8 to 10 degrees less than if it were off. Otherwise, you don't make cold air or get full blower.
Put on the solid top if you've got one.
