Is there a way to bypass heater fan switch?

[bullseye]

My interior heater fan will not come on after I cleaned up behind my dash. I only removed the heater switch and zip tied the wires.

I am thinking it must be the switch. Is there a way to bypass the switch to test this theory? Hopefully as easy as using a paperclip?

Pics of the female plug to the heater fan switch.

 

[Cheepjeep85]

if you are just wanting to test the motor look under the battery tray there is one wire connected to the fan motor disconnect it and run a power wire to it. i'm not sure what the pinout is on the plug. you can find the 12v term by using a test light or meter after you turn the ign switch on then you should be able to jump it out with the other terminals to test the "speeds". did you check to see if the fuse was blown? what about checking all of the plugs under the dash? there is a harness that runs over to the pass. side under the glove box to the resistor check to see if it is plugged up.

 

[John Strenk]

 

[bullseye]

if you are just wanting to test the motor look under the battery tray there is one wire connected to the fan motor disconnect it and run a power wire to it. i'm not sure what the pinout is on the plug. you can find the 12v term by using a test light or meter after you turn the ign switch on then you should be able to jump it out with the other terminals to test the "speeds". did you check to see if the fuse was blown? what about checking all of the plugs under the dash? there is a harness that runs over to the pass. side under the glove box to the resistor check to see if it is plugged up.

Fuse is good and wires plugged into resistor under air vent on passenger side. It's got to be the switch!

Going to test motor now.

 

[bullseye]

Success. I stuck a paperclip into the red and bridged over to each of the other wires. At the very least, I should have blown a fuse.

I then verified there was a current. In hindsight, I probably should have done that first.

That most likely eliminated the switch.

I then went to test motor as suggested. I went to pull the wire connector off but it didn't take any force to pull it off and the male end was corroded.

Took some sandpaper to it and reattached.

Plugged switch back in and tried it. Fan worked.

I must have knocked it loose when I took the battery tray out or back in...

 

[Cheepjeep85]

good deal glad you got it fixed. you really should do the blazer motor upgrade its well worth doing

 

[bullseye]

good deal glad you got it fixed. you really should do the blazer motor upgrade its well worth doing

I think I will wait until the original STB...

 

[Cheepjeep85]

STB...

 

[bullseye]

STB...

$hit$ the bed

 

[TDHofstetter]

:d :d :d :d :d

 

[Cheepjeep85]

ah gotcha,

 

[musciab]

Kind of on the same subject. I just bought what it said to be a 74 CJ5 with a 76 fiberglas tub. Now, I am trying to pick up where the previous owner left off in wiring, but it is a mess. Can someone give me detailed instructions on how to wire up the heater and reverse lights. I have a wiring diagram but it dosnt seem to be really clear. I need some help.

 

[TDHofstetter]

Oh, THAT's gonna' be fun!

Which wiring diagram do you have? There are excellent diagrams here and here:

Jeep Wiring Diagrams - 1974 and 1975 CJ
Jeep Wiring Diagrams - 1976 and 1977 CJ

You'll need to kinda' marry the two together. It shouldn't be too hard, though...

Do you have the '76's fuseblock, or are you working with the '74's underdash wiring? If you're working with the '74's wiring, the heater blower switch is powered directly off the ignition switch ("IGN" side) though an inline 15A fuse. If you're working with the '76's fuseblock, it takes its power from terminal #26 on the back of the fuseblock. From the blower switch to the heater blower, it's just a straight wiring run... but you MUST run a ground wire from the blower housing to the Jeep's ground (at the battery, the motor, or the frame). Otherwise, it won't blow.

The backup lights are pretty easy:

If '74 underdash wiring:
One wire from the "IGN" terminal on the ignition switch, through a 9A fuse to the reverse switch on the Transmission . Another wire from the other side of the reverse switch to both backup lights.

If '76 fuseblock:
One wire from the "Cigar lighter" fuse on the fuseblock (looks like terminal #32A from here) to the reverse switch on the Transmission . Another wire from the other side of the reverse switch to both backup lights.

EDIT: Oh, and... again, like the blower, you MUST run a ground from each of the taillight housings to the Jeep's frame or they won't light right and you may get some really strange lighting patterns when you try to use 'em - stuff like the turn signals lighting when you put the Jeep in reverse, like that.