Just need someone to tell me if i'm on the right track.
I've got a 88 5.7 IROC with twin electric fans.
This is how i think they are supposed to work.
left fan is controlled by ECM and comes on at a set temp.
right fan is controlled by a switch in the right hand side head and comes on at the switch temp, but also when the AC is on.
Is this correct so far?
To test fan operation if I bridge the A and B terminals on the ADL connector and turn the ignition on as if I am checking for fault codes, should both fans run because i only have the left one going and the here is no power at the plug of the right fan. I've even tried with the AC on and the pressure switch bridged but still no power. Is this normal?

 

there should be a relay for the passenger side fan near the front of the engine bay mounted on one of the fenders. Unplug the relay and short the power, and ground pins of the female side of the connector, and the fan should come on (the fans have constant 12v, orange wire I believe), so this can be done without the key in the ignition. You can also just test out those two pins in the relay connector with a multimeter to check if it has 12v or not. Hope this helps.

 

when u ground the connector only one fan will kick on since it's controlled by the computer the other fan you can ground the connector at the head an it should turn on if you have no power to that fan look at fusible links near battery and relay for fan

 

You are mostly correct. I wrote up a long article on this a few years back. Should answer precisely when and why the fans turn on.

https://www.thirdgen.org/forums/cool...ans-arent.html

 

ok so I found the relay and unplugged it then bridged the orange wire to the black (with red trace) and the driver side (left) fan came on. both fans have the same coloured (black with red trace)power wire so is there another relay that I haven't found

 

there's 1 relay per fan usually 1is near the drivers firewall and the other should be near the pass. side rad / battery area