no high heat!

heater blower motor-high doesnt work on my 78 cutlass!! i've owned it for 13 years, everything else works. fusible link?? maybe, but where?? any help would be appreciated greatly!!

[70ragtop]

The "high" setting on the blower motor uses a seperate fuse than the rest of the circuit. It will be an inline fuse with possibly a large guage purple wire found under the hood somewhere.

[gutlass]

purple wire, yes, runs from the blower motor to the relay( which i believe works)... wire is only 6 inches long and no fusible link. thats it for purplw wires tho. any other suggestions? (sam)

[70ragtop]

Look around under the hood, most likely on the drivers side. You are looking for an in-line fuse holder. I will see if I can dig up the diagram for this car.

[Oldsguy]

I have seen the heater control resistor block cause that problem. I is located in the air plenum (engine bay side) and has four wires running to it. It is mounted on the plenum with just two sheet metal screws, usually the block itself is shaped sort of like an oval. On the opposite side you will see three coils, these coils are actually RESISTORS, their length and guage determine how much resistance is offered to the blower fan. I would be willing to bet one of those coils are bad, you should see an interuptions where the wire has actually burned in two and therefore is an open to the fan circuit for the High setting. You can get a replacement from a local junkyard if your part store can't get it.

[ndiver63]

the resistor block is used for low and medium, When it goes to high there is a bypass wire Red 10/8 gauge wire that run directly into the blower. place the switch on High and verify you have 12 volts through the block and on the other side a lot of time on the connector block it heats up and burns out.

[Oldsguy]

I should have remembered that! I almost forgot about this thread as it is almost a year old! Resistor for low and medium, full 12 volts for high, of course!!!!