Help! Cooling Fan and Blower Motor

[Chrobo]

Ok here is my problem, on my 88 Corvette, the coolant fan won't turn on at all. I've replaced the relay and nothing happened. I also replaced the motor, still no luck. When I jump the fan at the relay it turns on. Also, my blower motor wont turn off, even if the car is off. I currently have it unplugged so it wont run my battery down. All the fuses are good. I don't know if the two problems are related. I don't really know where to go from here.

 

[Hib Halverson]

Have you tested the cooling fan system using the troubleshooting info in the factory service manual?

Have you looked in the service manual sections on hvac to see if there is diagnostic info for a blower motor that will not shut off?

 

[patrickj]

blower motor

I ran into a similar problem fans would not come on at all.There are two separate relays for this system one on the fender well and one behind the battery area near the door jamb.I got tired of the over heating so i installed a switch under the hood turns on one fan or both and also has an off position.I bought it from mid America Mamotorworks.com cheap too.Also check a/c pressure switches.Oh dont forget the fan temp switch in the block I believe that is a normally open switch

 

[Hib Halverson]

C4 fans are either controlled by the ECM or by a simple thermostatic switch or, sometimes, both.

If there's a second relay, that's the first place I'd look. If you find that relay ok, then I'd go looking in the FSM for 88 to see which fan actuation method your engine uses then troubleshoot the electrics of the cooling fan sys. with the manual's info.

 

[vetteoz]

Also, my blower motor wont turn off, even if the car is off. I currently have it unplugged so it wont run my battery down.

Seperate problem
Blower control module is faulty ; it has a direct feed to the motor through a fusible link
Is mounted in top of ducting on firewall

 

[vetteoz]

I.Also check a/c pressure switches.Oh dont forget the fan temp switch in the block I believe that is a normally open switch

Switch in drv side head (86 -89 ) controls aux fan in front of radiator ONLY ( if fitted )
Faulty A/c switch will make Pri fan run full time or not come on when A/c running

l.There are two separate relays for this system one on the fender well and one behind the battery area near the door jamb.

Only if you have both fans fitted .Aux fan was a option on most cars