Heater-a/c fuse blowing problem

[HondaTech86]

My friend has a 1991 s-10 Blazer... 4.3, 4x4, automatic. It has been blowing the heater and a/c fuse. It seems to only blow when starting the vehicle. It does not blow after driving for a while. But it also seems to blow when the blower is on high. About a year or so ago, the blower was replaced. He has had no blown fuse problems up until this late fall. Any knowledge would be greatly appreciated.

[Mikado14]

Originally Posted by HondaTech86

My friend has a 1991 s-10 Blazer... 4.3, 4x4, automatic. It has been blowing the heater and a/c fuse. It seems to only blow when starting the vehicle. It does not blow after driving for a while. But it also seems to blow when the blower is on high. About a year or so ago, the blower was replaced. He has had no blown fuse problems up until this late fall. Any knowledge would be greatly appreciated.

Fuses are cheap. Try unplugging the connector at the A/C clutch and try it. If the fuse doesn't blow, it's the clutch coil which should be diode suppressed and is bad. If the fuse blows, try unplugging the heater blower. If it doesn't blow, the heater blower is bad.

This is a start.

[HondaTech86]

Thanks I'll give that a try.

[Fireplug]

Also seen the high blow relay go bad(high resistance) causing the fuse to overheat and melt/blow