10a Fuse On Heater Relay Blowing

[Risstanomak]

Hey, the 10A fuse keeps blowing in the heater relay slot. I took out the blower motor and it bench tests fine. The resistor seems ok too. Everything worked with a 30A fuse but I took it out. A 10A fuse even blows when the heater relay is taken out. Any thoughts? Please help, I've researched the site and am stumped since it keeps blowing even when the relay is taken out. As soon as the key is turned the fuse blows.

 

[luv2rallye]

You have a short to ground in the blower switch (from pin 8 (blue/red wire) to pin 5 (black wire). It often fails this way. Disconnect it's 8 pin connector to verify that the fuse stops blowing. If this not the problem report back.

 

[Risstanomak]

the connector for the switch is behind the heater control assembly or near the actual blower motor?

 

[luv2rallye]

I suspect it's behind the heater control assembly.

 

[Risstanomak]

I have disconnected everything I know to be on that circuit. The rear defrost, blower moter, AC, heater control assembly, and the relay. The fuse still blows everytime I turn the key. Any idea what I could be missing?

 

[luv2rallye]

Well then you probably have a wire shorting to ground (or to another wire which goes to ground). If you removed the blower motor relay and disconnected the blower switch 8 pin connector and you still blow the 10A heater relay fuse, then the only place the short can be is from the load side of the 10A fuse to the blower switch pin 8 (blue/red wire). Check this wire. You can replace the 10A fuse with a small 12 volt light bulb for testing purposes so you don't keep blowing fuses (light on means short). If not in the wire you'll probably have to remove the interior fusebox and relay socket assembly to look for a short on the back side.