2002 Sport Trac eating blower fan relays

[TEW]

2002 sport trac keeps burning out fan blower relays, fan motor was stuck, replaced it with new one & also replaced relay, all speeds work fine on fan but relay only lasts a couple days at most. relay gets really hot, has even charred the plastic around where it plugs in in fuse panel, the plugs are good and tight, no loose connections anywhere. Could the blower motor resistor be fried and causing this over current draw. Any ideas would be greatly appreciated.

 

[JohnnyO]

If you already replaced the blower motor then I would look at the ballast resistor. I already had it replaced in my 08 Trac. If that's not it then I got nothin' else.

Basically the blower runs at full speed (or thinks it runs at full speed) all the time but the ballast resistor slows it down to the other speeds.

 

[TEW]

If you already replaced the blower motor then I would look at the ballast resistor. I already had it replaced in my 08 Trac. If that's not it then I got nothin' else.

Basically the blower runs at full speed (or thinks it runs at full speed) all the time but the ballast resistor slows it down to the other speeds.

Replaced the resistor, it looked fine, but replaced it anyway. Still have same problem.I opened these blown relays up and found they are burned out on the coil side not the contactor side, what could cause the fan switch to send too much current to the coil on the relay?

7-4-12 Correction, after further checking, it is not the coil burning out it is the contactor overheating & loosing connection as though the blower is pulling too much current.

 

[bdmaash]

check ground wire on the fan, and also for short to ground on power wire to fan

it could also be power to the relay coil is not clean (bad connection) and consistent causing the switched contacts to chatter.