HVAC fan control '85 Vette

[nmacdonald]

I've done a search on this issue and am not certain I've accurately located the problem or the solution.

While on our most recent road trip when I turned the fan on for the heater, nothing happened. Then after 30 minutes or so, it would come back on. Then it would stop. Over the past few days it hasn't come on at all.

When I turn the switch I can hear a "relay" clicking somewhere, but I'm not certain where it is.

The rear defroster doesn't seem to work either, so I'm not sure it the two are related.

Any suggestions on where I can find this relay. The Shop Manual and the Chiltons manual aren't giving me much help.

Other posts have indicated that there is an in-line fuse on the right side of the IP that controls the fan and it's the same one as the horn. Is this the same for the 85's?

Thanks.....

 

[ErnieN85]

Three things to check the switch, (in dash) the resistor's (in the blower housing under the wire harness &plug) the relay under the blower housing. and the blower motor itself.

the switch selects the resistors for speeds 1-3 and the relay ia a direct connection for high. now if none of these work it's most likely the blower motor itself is bad. try unpluging it and running power direct from the battery (wear gloves) if it' shorts it (the wire) will get hot real fast!

 

[G Winter]

Check the connection on the fan motor. Usually a spade terminal is used and they do on occasion get hot and burn away . I noticed you said it was intermitent at first and you hear the relay click , which I assume is when you turn the switch to high ? If the connection is not bad all of what Ernie said applies except I would use a volt meter on the wire to the fan motor and try all fan speeds. On high it should be 12 volts and each speed slower should be a lower voltage. The relay for the fan motor is usually a single throw double pole. It directs the current to either the motor or the resistor set.ON some it is just a single throw single pole which goes only to the motor. So if the relay is bad it is possible for none of the speeds to work . I don't think it would be the switch in the dash if your relay is clicking .You did check for blown fuses ? Hope this helps .

 

[nmacdonald]

Thanks Guys.... not sure what's up. Worked just fine today!!! All day!!! Did some pokin' and prodin' yesterday so perhaps I fixed it without knowing that I fixed it.... or maybe it's just teasin' me! :L

Must be a gremlin or somethin' like that.

 

[First C4]

Do you have the C68 electronic climate control or the C60

 

[nmacdonald]

Neither - I have the good old lever and knob set up.

I did take things apart as best I could, cleaned contacts wherever I could find them inside and out. Right now it's working - not sure why or what, but it's working.:confused

Thanks for all the feedback and assistance.