Wiring for dual fans

[captndave737]

Of course you can. Depends how you wire them. I used the stock connector, pin A to provide power to the coils of both my fan relays. The other side of the relay coils are grounded. I don't use pins B&C , ground and high speed signals. When my fans run they are always on high. One side of the relay contacts go through an inline fuse to the battery and the other side to ground. It's a pretty simple system.

Since I rebuilt my wiring harness I've eliminated all the high speed and delay circuitry from the system. I also cut off the stock connector and replaced it with a single pin weather pack connector that goes to the low speed fan relay. I removed all wires I don't use under the hood.

 

[captndave737]

Of course you can. Depends how you wire them. I used the stock connector, pin A to provide power to the coils of both my fan relays. The other side of the relay coils are grounded. I don't use pins B&C , ground and high speed signals. When my fans run they are always on high. One side of the relay contacts go through an inline fuse to the battery and the other side to ground. It's a pretty simple system.

Since I rebuilt my wiring harness I've eliminated all the high speed and delay circuitry from the system. I also cut off the stock connector and replaced it with a single pin weather pack connector that goes to the low speed fan relay. I removed all wires I don't use under the hood.[/QUOTE

 

[captndave737]

Do the fan relays you have each power a single fan? The RamCharger fans each have 2 windings. When ONE set is powered the fans run on low when BOTH sets of windings are powered they run on high.

If you want factory style High/Low speed control you can use the stock connector. If they have 2 windings you can use the stock harness to power them through the ECM and have High and Low speed. If they are powered separately you can use it to power one fan with the low speed signal and the other with high.

The ECM only commands a High signal from the Fan Delay circuitry who's main function is to run down your battery while your sleeping. Hopefully you've taken that relay out and destroyed it so it can't do any more damage. 2 other things things make them run on high and it's not ECM related. Temp over ( I think ) 210 Deg., might be 230, controlled by the Temp switch on the intake manifold and AC pressure over 300 Psi. taken from the AC taken from the AC High pressure switch on the AC line above the compressor.

I don't like my temps. getting nearly that high so I have it wired so when the ECM signals low speed my fans come on high. With an aluminum radiator and a 180 deg thermostat my temps have never gone above 187 even on 100+ deg days except when a relay died.

 

[captndave737]

Another schematic.