The fan delay relay is EVIL and really not necessary. In fact it's more trouble than what it's worth. I had removed mine back in 1986 and have run without it since then. Here's why the relay is not a good thing to have:
1. It is an unsealed relay - moisture and water gets inside and destroys the circuitry.
2. The two plugs on the relay have a potential for causing big-time problems because one plug has switched 12 volts and the other has constant 12 volts. The potential here is that, under certain conditions, the relay can fail due to internal rusting, and cause the constant 12 volts to short out to the switched 12 volts - the car won't shut off (I've seen this happen twice over the years)!
3. Because of the potential mentioned above, the relay can cause a current trickle to ground (there is a ground wire as well) leading to battery drain when parked.
If your coolant fan and radiator are upgraded, you really don't need the extra fan during shutdown anyway. Granted, our 160 degree thermostat creates a bigger demand on our cooling system, you should upgrade anyway.
The AC line pressure can demand high speed coolant fan, initiating the delay relay, or, high coolant temperature as sensed by the one wire sensor under the throttle linkage, initiates the delay relay. BUT, the coolant fan should not run by itself if it did not run when you turned the key off...it can only be initiated during key-on condition.
Hope it makes sense,
John Spina
http://www.casperselectronics.com
1. It is an unsealed relay - moisture and water gets inside and destroys the circuitry.
2. The two plugs on the relay have a potential for causing big-time problems because one plug has switched 12 volts and the other has constant 12 volts. The potential here is that, under certain conditions, the relay can fail due to internal rusting, and cause the constant 12 volts to short out to the switched 12 volts - the car won't shut off (I've seen this happen twice over the years)!
3. Because of the potential mentioned above, the relay can cause a current trickle to ground (there is a ground wire as well) leading to battery drain when parked.
If your coolant fan and radiator are upgraded, you really don't need the extra fan during shutdown anyway. Granted, our 160 degree thermostat creates a bigger demand on our cooling system, you should upgrade anyway.
The AC line pressure can demand high speed coolant fan, initiating the delay relay, or, high coolant temperature as sensed by the one wire sensor under the throttle linkage, initiates the delay relay. BUT, the coolant fan should not run by itself if it did not run when you turned the key off...it can only be initiated during key-on condition.
Hope it makes sense,
John Spina
http://www.casperselectronics.com
