Chevelles.com banner

1 - 5 of 5 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter #1
if you remember my heater fan switch was heating to the point where you would burn your finger on the switch once it was turned on. I had a new switch, installed it and sure as [email protected]# the old one was burned, the phenolic back panel was dark brown, and the metal housing had signs of heat/fire expulsion around the sides. what could cause this????? I did have a window leak that I have fixed, but the switch is so far away from the path of the water I don't think that was it. I am concerned because I think the new switch might be building up heat too. I don't know why? I am the second owner of this car. I bought it from a little old man so I know no wires were cut, and every gauge I added went right to the fuse block with a fuse, so I am fairly certain there are no open wires or cut and chafed wires. any help would be great, thank's in advance, mike and the car is a 70 el camino by the way
 

·
Premium Member
Joined
·
2,223 Posts
This is my opinion on this FWIW

There are two motors used on a these cars. One is a smaller motor for heat only, the other is larger and is for A/C cars. It's possible that someone installed the larger motor which would draw higher current which is above the rating of the fan switch. If you have the larger motor it should be replaced.

It's not uncommon to have overheating on the at this switch even if it has the correct motor. A slightly lose or high resistance connection will cause the connector to heat in time it just gets worse.

I suggest you replace the wiring from the switch to the blower speed resistor as a complete harness or you can use the existing wiring and install generic female tab connectors. If you don't use a good quality crimping tool you can end up with the same problem.

You won't find a part # for this harness ass it is part of the dash harness but I'm sure some of the wiring harness manufactures will make one up for you.

I hope this is not considered a for sale ad. I have the correct tools, connectors, wire terminals and wire. e-mail if interrested.
 

·
Premium Member
Joined
·
13,553 Posts
The same thing happens on todays vehicles. At the shop where I work, we replace heater fan switches that are burnt like that and our theory is that the operators of these vehicles leave the fan on during the day, esp in this winter weather and the constant operation of the blower eventually causes the blower motors to wear and that causes excess current flow and burns the switch.
 

·
Registered
Joined
·
7,762 Posts
Ever tried unplugging the blower resistor connector and/or the relay connector under the hood? See if the switch gets hot with those connectors unplugged.
*EDIT*
Wonder if the poor frame ground may have something to do with things? Wonder if somehow the motor doesn't have a decent ground it's affecting the switch? Just wondering.
 

·
Premium Member
Joined
·
2,223 Posts
I agree with Leo. I couldn't say with certainty that the current increases as the motor speed decreases. Tested tonight at home and the results confirmed it. So if your motor is slowing do to wear and/or drying bearings. The current will increase.

I recommended replacing the wiring because you would have new wire terminals for the best possible connection to the switch and the speed resistors. It would be farley easy to replace and the cost would be minimal.

Also either something you stated in past posts or I just assumed, but I'm thinking you don't have an A/C-heat unit. If you do have A/C then disreguard the cheep easy replacement of the wiring.
 
1 - 5 of 5 Posts
Top