trifive

The fan on my 1991 corvette ac/heater only blows on high it will cut off and on with no problem from the controls.

I have replaced the CORVETTE C4 HVAC ELECTRONIC CLIMATE AC HEAT CONTROL IN THE DASH and also a new Heater blower control module

So other than that what else controls the speed of the fan

The digital control shows the speed going from 1 to 10 no problem when selected but the fan speed does not change,

Any ideas appreciate.

Is their a verible resister or something I am missing.

Thanks

otis

trifive

I found the problem, You have to remove the radiator overflow tank and hidden behind it on the firewall is a 5 amp fuse. It is so hidden that it does not look like a fuse it looks like a relay switch, but if you pull down on the 2 wires a fuse popped out, I bet tons of people spent useless money like I did because the corvette dealer and many others on the net also pointed to the parts I replaced with no solution.

Otis

WVZR-1

A FSM (Factory Service Manual) would also have likely directed you towards the "first" components to check. The first diagnostics are to check "related" fuses which the one you just found is included. The location of the fuses are also included.

The FSM regardless of price would have certainly saved you money, time and much aggravation likely!!

trifive

Did not have factory service manual, But the first thing I checked was all the fuses, I then looked at all the corvette sites and all over the net and lots of other guys have the same issue, they changed all the parts I did and even the fan motor with no results,

But I never seen any one give them the answer I found for myself nor did you give an answer until after I found the answer.

You have to remove the radiator overflow tank to find a ting 5 amp fuses hidden behind the tank, that is certainly a crappy design job by gm on this one, they should have put the fuse in the fuse box or atleast exposed somewhere near the fan motor, not hidden.

Otis