10-07-2013, 10:58 AM
Join Date: Jul 2010
Location: Florida West Coast
Re: cooling fan problem
As far as I know, you are correct in that the fans should not run with the ignition switch off. Here is what I would do:
First of all, are you sure there hasn't been a switch installed to force the fans to run all the time the switch is on? It is not that rare for the owner to install such a switch.
If no such added switch is found:
Remove all 3 fan relays.
If the fan(s) still run, check for a short of the light blue or white wires at the fans to battery voltage. Very unlikely ... I know.
If the fan(s) do not run, plug in the relays one at a time (ignition off) until the fan(s) runs again. Then check for a short-to-ground of either the dark blue (for fan 2 or fan 3 relay) or dark green (for fan 1 relay)wires.
If no short-to-ground is found, you may have a shorted PCM, again very unlikely.
1998 Trans Am, LS1, Automatic, stock all the way.