Blower running at 1 speed

[chriskinzel]

The heater and A/C fan always runs at the same speed. I have replaced the module, but it still runs at only 1 speed. Any ideas where to go next. I have had the car since November and it was this way when I bought it. 1991 with 50k on it.

[gbrtng]

The heater and A/C fan always runs at the same speed. I have replaced the module, but it still runs at only 1 speed. Any ideas where to go next. I have had the car since November and it was this way when I bought it. 1991 with 50k on it.
Meaning you can't adjust the blower speed from the control head?
And what module did you replace?

[chriskinzel]

Yes, only 1 speed. When it is on auto it blows 1 speed. When ii try to change speed manually with the fan arrows nothing happens. It just blows at the same speed. I replaced the blower module in the engine compartment.

[GOLDCYLON]

Replace the blower unit. Mine had the same problem. I could tap the outside of the fan blower housing and the fan speed would actually pickup.

[chriskinzel]

I guess that would be the next part to replace. Thanks goldcylon

[phrogs]

If you need those switches on that are in the engine compartment on the AC cover I have them if you need them

Not sure what they are retail but Lets say $50 plus shipping.

[gbrtng]

Yes, only 1 speed. When it is on auto it blows 1 speed. When ii try to change speed manually with the fan arrows nothing happens. It just blows at the same speed. I replaced the blower module in the engine compartment.
When you change speed does the display change?

[chriskinzel]

The display will change fan speed numbers but the fan runs at a constant speed. I have pulled the fuses by the glove box but nothing changes.

[GOLDCYLON]

Yep been there and done that. Replace the blower unit which is not ZR-1 specific You can find them all day for any C4 NIB for less than $50. Some with or without the squirrel case which you can simply reuse. I suggest relaxing the bolts on the inner fender well obviouslly on the passenger side. Removing the blower bolts is easy but be mindful of the orifice drain tube position on the underside of the unit. If you dont relax the inside of the fender well you will not have enough room to pull the unit out due to the squirrel cage gets in the way. Very simple job to do and should not take you any more than 30 mins.

[chriskinzel]

OK. This little problem is kicking my a**. I just replaced the blower motor. Now it seems to move a little more air, but it still runs at only 1 speed! Anyone have any other ideas? This shouldn't be as hard as it is. Thanks.

[GOLDCYLON]

OK. This little problem is kicking my a**. I just replaced the blower motor. Now it seems to move a little more air, but it still runs at only 1 speed! Anyone have any other ideas? This shouldn't be as hard as it is. Thanks.

Well this sucks. You already replaced the blower controller resistor next to the motor correct? That being the case either the head unit or the programmer above the accelerator is the culprit. Before you buy any more parts I suggest using your red factory service manual fault trees. Then with some codes we can see what is really going on. GC

[chriskinzel]

Yea, I guess I will need the book sooner or later so I will get one on order. Thanks to all who tried to help. This really is a good group of people. Chris:dancing

[GOLDCYLON]

Yea, I guess I will need the book sooner or later so I will get one on order. Thanks to all who tried to help. This really is a good group of people. Chris:dancing


Let us know if you figure it out so you can close the post and help the next member out. FSMs are a great investment to keep your car running.

[gbrtng]

Well this sucks. You already replaced the blower controller resistor next to the motor correct? That being the case either the head unit or the programmer above the accelerator is the culprit. Before you buy any more parts I suggest using your red factory service manual fault trees. Then with some codes we can see what is really going on. GC
Looking at section 8 of the FSM I see that the CCM is also connected to the programmer. You'll have to back-probe some of the interconnect wires to see where the fault originates. At least it's a hard fault - everything I get hit with are intermittents - but my guess is the programmer.

[RHanselman]

I have a 96 C4 parts car there in Farmington at Corvette Recycling. You can try both parts and then buy the one you need....

[chriskinzel]

That sounds like my best option. PM me and I will make arrangement on getting parts!
You guys are the best:handshak:

[GOLDCYLON]

Nice of you Ron! Not sure if the programmer will work however I think the head unit is the same. GC

[RHanselman]

Sent...