Questionthe cooling fans on my 94 roadmaster are not working. i have checked the fans and they are ok, i have also replaced the relays and still nothing. one fan will come on if i turn the a/c on but not for long.
AnswerHello Metrik,
Roadmasters are out of my league, but the fans are controlled by relays.
I would say the one that comes on when the a/c comes on, is probably working correctly. It will come on whenever the compressor is on. I really don't know if there is a condition where it will come on due to engine heat or not.
But the other fan does come on due to engine heat. There is a coolant temperature sensor that sends a signal to the ecm, which uses that information to adjust fuel mix, timing, and I am sure it turns the fan relay on as needed due to that signal also.
I would check the relay for that fan, and probably swap it with one of the other relays that are the same, like maybe the horn relay, and see of the failure to operate problem goes to the replacement circuit with the relay, or stays with the fan.
If it travels with the relay, just replace the relay.
If it stays with the fan, I would check the temperature sensor.
Here is a link to a forum subject on the coolant temp sensor, and how important it is, as well as a chart for testing them.
http://us.f818.mail.yahoo.com/ym/ShowFolder?rb=Coolant%20temp%20sensor%20ohm%20s...
Van
