Cooling Fan Relay
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,672
Likes: 810
From: Saskatoon Sask.
Cooling Fan Relay
Hello to everyone. This is my first post and my first Corvette, so please bear with me. I am restoring a 1987 coupe and have just completed the engine. I have replaced all sensors and have tried to get the cooling fan relay to turn on by grounding the wire on the sensor behind the dipstick on the right head. According to Haynes book, this wire is a temperature override to the ECM. The fan does come on by the ECM. This wire is shown as tapped into the green-white stripe wire going from the ECM to the fan relay. Does anyone know the actual location where this wire is spliced in? Any help much appreicated.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Cooling Fan Relay (arbee)
The sensor on the right side of the engine is the temperature sender for the cluster temperature gauge only. On the left side of the engine between cylinders 1 and 3 is a thermostatic switch that grounds at 238 F and if you ground the wire on it, the auxiliary fan in front of the radiator will turn on.
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,672
Likes: 810
From: Saskatoon Sask.
Re: Cooling Fan Relay (jfb)
Thanks for the reply JFB but my car has no aux. cooling fan and there is no sensor between the 1 and 3. According to my manual, the temperature unit for the cluster is in front of the intake manifold beside the cold start sensor and the water supply pipe to the throttle body.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Cooling Fan Relay (arbee)
The temperature sensor on the front of the engine under the MAF supplies coolant temperature info only to the ECM and the ECM turns on the fan at 228 F. You can force the fan on by putting a toggle switch on the green/white wire on the fan relay to ground. When grounding the grn/wh wire , the fan relay coil comes on and the fan runs. My 87 has the aux fan.
Thread Starter
Melting Slicks
Joined: Feb 2003
Posts: 2,672
Likes: 810
From: Saskatoon Sask.
Re: Cooling Fan Relay (jfb)
Thanks for the info JFB. The manual switch was my next question. I don't like the thought of those high temps in stop and go traffic. Don't know why my car never had the aux. fan. Production date maybe(Sept. '86)
