blower problem
Racer
Joined: Nov 2010
Posts: 460
Likes: 1
From: Oliphant Ontario
Can't be a short. Blower motors are just one speed, the resistor then drops the voltage so they run slower. If it runs at slow speed, it runs. At high speed, it should bypass the resistor and run a direct 12V. Make sure the new motor runs at a full 12v (should) and without the fan make sure the power to it has 12V when you switch to high.
The motor will draw more amperage with more voltage so if you had a 5amp fuse in where it should be a 10 (don't actually know what it's supposed to be) it would run at low speed but draw too much at high and pop the fuse.
Try each of the above tests and if it all passes those, go up 5amps on the fuse and see what happens. It is possible the motor is either the wrong one or wound for higher speed than the original (which would require more power at full).
The motor will draw more amperage with more voltage so if you had a 5amp fuse in where it should be a 10 (don't actually know what it's supposed to be) it would run at low speed but draw too much at high and pop the fuse.
Try each of the above tests and if it all passes those, go up 5amps on the fuse and see what happens. It is possible the motor is either the wrong one or wound for higher speed than the original (which would require more power at full).
Thread Starter
Instructor
Joined: Aug 2001
Posts: 110
Likes: 0
From: Wichita KS
i didnt replace the motor, just the relay. If the motor can not have a short, since low speed works, than the new relay must be bad, its the only new addition to the system.
the blower fuse is a 25 amp fuse.
matt
the blower fuse is a 25 amp fuse.
matt
Racer
Joined: Nov 2010
Posts: 460
Likes: 1
From: Oliphant Ontario
Ok, did a quick read of the FSM for blower testing. Seems that in all speeds other than full, the blower motor is powered but one or more resistors depending on speed selection. Full speed the relay closes and bypasses the resistors and sends a direct battery to the blower. That said.. A short/grd in the wire feeding the relay (shows orange for this one/87) or a defective relay, or the wrong relay (wrong pins / functions) would cause a short only on high but leave all other speeds ok..
2nd Gear
Joined: Jan 2007
Posts: 2
Likes: 0
did the fuse blowing problem on the high speed blower fan ever get resolved? i have an 84 with the same problem. i have replaced the resistor, high speed relay, and the blower motor. it still blows the fuse instantly when you turn it to high
