05 Envoy 5.3 Fan

[shannons86]

I have put a 5.3 in a 56 Ford F100 for a customer, I have got everything going but I cant seem to get the fan to come on. I have tried everything I can think of and have been searching the net. Could anybdy give me some hints on what to try? I would greatly appreciate it. It is a standard 16" electric fan. I believe he bought it from advance. Wondering if this could possibly be the problem. Thanks

[99blackFRC]

It would help if you told us what changes you've made to the file, how you rigged up the relay/fan, etc.. Can you post your file?

BTW, I run an '05 Envoy 5.3 in my Jeep w/electric fan, so it is possible

[shannons86]

I used a normal 5 prong relay. It is wired just like the factory setup. I am using the white/black wire to power the relay out of the ecu. Pin number 36 connector C1. I can touch power to this and everything works great. I just cant seem to get the power out of the ecu. I havent done anything with the Hall sensor wires for the original fan either. Here is the tune that is currently in it I have tried alot of diffrent configs to try but no luck. Thanks

[99blackFRC]

Try changing fan type to Discrete.

IIRC, the ECM output to your fan relay is a switched ground. Other side of coil will go to 12v.

[shannons86]

ok I have tried it both ways pwm electric and discrete. no luck either way. What I have found, the ecm wire not hooked up. When I tell the fan to come on it goes to ground. Of course when the relay is hooked up with no path to ground power runs through the coil. If that power is in contact with the ecu wire it defaults out and has nothing. So I thought about a diode, put it inline to where the power cant get back to the ecu, I can tell the fan to turn on nothing happens, it seems as if the ecu cant pull the 12v to ground so it defaults out and then the ecu wire has nothing on it again untill i cycle the key. I hope this helps somebody, Sorry busy at the shop today, didnt have a lot of time to write this out clearly. Thanks again.