Fan Fail Bypass Fix Alternative

[jwit6@xxxx]

Here's a simple Fan Fail Module fix to make the Fan Fail Light come on only 
when either the cooling fan curcuit breaker thermal trip has opened, or the 
Cooling Fan Relay has failed. It will only illuminate the light if the fans 
are supposed to be running and are not getting voltage. Some of the simple 
fixes like the early bypass, and the thing with 2 fuses that you see one of 
the vendors selling, make the Fan Fail light come on and stay on everytime 
the fans are supposed to be running. This is backwards. You get to watch it 
turn on and off. One suggestion I saw was to put tape over the "FAIL" portion 
of the panel. 

I've put a hand drawn schematic of the before and after socket wiring in the 
photo section under "Techie Stuff" so you can see what you have to do.
Anyway, if you rewire the existing Fan Fail Module socket you can replace it 
with a standard accessory relay just like the cooling fan relay. I used a 
Borg Warner R682.

As usual disconnect the battery.
Open up the relay compartment. 
Locate the first row of relays. Thats the row closest to you as you face the 
rear of the car and look down into the relay compartment. 
Remove the Fan Fail Module (Big Blue module if it's still in there. It's the 
first one on the passenger side)
Remove the Low Beam Relay (First relay on the drivers side)
Remove the Cooling Fan Relay (Second on the passenger side next to the old 
Fan Fail Module)
You can now remove the two screws holding the relay socket assy to the metal 
tray.
You can now lift the socket assy up and slide the Fan Fail Relay socket off 
of the remaining sockets in order to perform the rewire per the schematic.

I would recommend soldering all connections, insulating bare wires and 
generally doing this in a professional manner. Introducing 15amp fuses in the 
black/green wires to the fans is optional in my mind but not a bad idea. You 
can use all the existing socket connectors simply by cutting the existing 
wires about an inch from the socket connectors, and neatly soldering your new 
connections to the remaining wire stubs.

This mod works by using a standard accessory relay in the old Fan Fail Module 
socket. The normally closed pins of the new relay (30/51 and 87A) are held 
open any time the cooling fan relay is supposed to be energized and there is 
voltage going to the fans. If the cooling fan relay is being told to energize 
and kick on the fans, but there is no voltage to the fans, then the light 
will come on. In which case you have either a circuit breaker thermal trip, 
cooling fan relay failure, or other wiring problems. It will not signal you 
if you pop the optional 15amp fuses but with the stock circuit breaker I'm 
not sure you really need them anyway. (Also removing the spade connectors 
going to both circuit breakers and soldering the wires directly is a really 
good idea.)

Resecure the relay socket assy and reinstall the relays you removed plus 
install the new one. All are the same, and the old fail module is no longer 
required. You can test by starting the car and running the air with the 
cooling fan relay removed. You should have a fan fail light.

I've already installed this and so far it seems ok. Let me know what you guys 
think. 
Jim 6147