Gm Computer Electric Fan Relay Wiring Diagram. Page 4 optional relay overrides temp sensor and turns on fans when ac is turned on battery 86 30 87 85 86 30 87 85 optional override switch turns on fan by passing temp sensor and ac relay. Httpsamznto377klrpthose fans fit perfect on 68 72 gm a body cars bu.
Gm trucks were fitted with a mechanical fan until 2005 so those pcm calibrations do not have provision for electric fan control with ac on. Each should have the capacity of a single fan. The connected wire measured 75 volts and the unconnected measured 45 volts.
Blueconnect this wire to your right front turn signal lamp socketif you are using a single front turn light with an 1157 or dual filament bulb this wire should be connected to the high.
So if you wish to get all these great graphics about electric cooling fan wiring diagram. If it does not handle 20 amps you may use a relay see diagram below. If repair was not necessary go to step 21. It is recommended that this wire be routed and connected to a fan relay.