fast400

iTrader: (1)

I have a 2006 L59 5.3 Silverado engine in my 69 Firebird. I rewired the original harness. I wired the dual fans the same way GM did using three relays. When I finished I tested using HP scanner to activate the high and low fan. Everything was perfect and the fans came on as they should.

Next I ran the engine. I've set fan 1 to come on at 200. The temp hit 208....no fan! I'm lost as to why I'm able to trigger the fan, but it won't come on by itself.
Anyone run into this before??

N21923

iTrader: (8)

You've got 12v on the other side of the relay coils, right?

poconojoe

iTrader: (43)

Set the temp real low, like 170 and see if they work.

fast400

iTrader: (1)

Ran the engine again today. I guess my cooling system is too good!! Idle for about 10-15 minutes (80degrees outside). Temp never hit 200, so I turned off for a minute, then turned back on and voila finally hit 200 for all of 30 seconds....long enough for the fan to kick on.

fast400

iTrader: (1)

I think there is a difference in temp sender and pcm temp sender which is why I was seeing a higher temp on one, but not the other.