My Grand Am ('91, 2.5L LE, 100k miles) overheats when idling or in stop and go traffic. Engine cools fine at speeds over 35 mph. Lost coolant the first time it happened, filled it up 2 times and now all the air seems to be out the system. Checked the fan, it does not work when the car is at 230F, while normal operating temp is 160F (maybe 180F not sure), but the fan motor works if directly connected to battery. Tried to check relay, found 4 on the firewall, one with wire colors almost (LT GR instead of DK GR) matching wiring diagram, pulled it out and checked it. Relay switches if + is connected to terminal 85 and - to terminal 86, Hayes says the relay should work with the opposite connections, but it doesn't do that. Checked all other relay's, 2 work either way, 1 works as the first.
I'm just confused, am I checking the good relay? How are they supposed to work? And what would be next?
All input welcome. Thanks!
And just out of curiosity, I have a Fuel pump relay, a A/C relay and a coolant fan relay, what does the fourth one do?