no high heat!

September 16th, 2003, 05:18 AM

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 · September 17th, 2003, 05:29 PM

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 · September 18th, 2003, 05:01 AM

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 · September 19th, 2003, 02:04 PM

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 · June 17th, 2004, 11:49 AM

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 · August 31st, 2006, 10:07 AM

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 · September 1st, 2006, 06:04 AM

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!!!!

September 17th, 2003, 05:29 PM	#2 (permalink)
70ragtop Member Join Date: Dec 2001 Location: Dallas, Texas Posts: 32	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. __________________ Jeff Herbert (70RagTop) Dallas TX 70 Cutlass Supreme Convertible 68 Cutlass S Convertible 72 Cutlass Supreme Hardtop

September 19th, 2003, 02:04 PM	#4 (permalink)
70ragtop Member Join Date: Dec 2001 Location: Dallas, Texas Posts: 32	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. __________________ Jeff Herbert (70RagTop) Dallas TX 70 Cutlass Supreme Convertible 68 Cutlass S Convertible 72 Cutlass Supreme Hardtop

June 17th, 2004, 11:49 AM	#5 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	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. __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

September 1st, 2006, 06:04 AM	#7 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	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!!!! __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

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September 16th, 2003, 05:18 AM	#1 (permalink)
<sammy> Guest Posts: n/a	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!!

September 18th, 2003, 05:01 AM	#3 (permalink)
gutlass Junior Member Join Date: Sep 2003 Posts: 1	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)

August 31st, 2006, 10:07 AM	#6 (permalink)
ndiver63 Junior Member Join Date: Aug 2006 Posts: 9	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.

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