76 Junior Heater Blower Switch Wiring

Jube · #1 (**permalink**) 04-07-2008, 12:57 PM

Hi Guys,
My Junior's heater hasn't according to the previous owner been working for years.

I thought I would check the basics and found that the blower switch had a wire off it. (The Black wire which seems to fit on the top left spade connector looking from above and which then goes on to the cigarette lighter)

I checked this with my wiring diagram (Thanks Papajam) and the wire looks like it should be connected to pin 8. I replaced the wire in what i thought was it's correct position and Fuse 3 blew!!

Has anybody got a piccie of the rear of the blower switch please - I know it's long shot but it's worth a try. Otherwise, could someone please confirm which pin number 8 is please?

If I have fitted the wire to the correct pin could it have been removed deliberately for any reason and is this why the fuse is blowing?

Many thanks in advance.
Julian.

**papajam** · #2 (**permalink**) 04-07-2008, 03:54 PM

Perfect timing! I changed out the blower switch on a 74 GTV just yesterday. Pic of the switch shows terminal 8 (the broken terminal on this switch) in the lower right position. Terminal #1 is on the upper left.
Also note that with the switch wired as per the diagram, with the yellow/black on terminal #4 and the yellow on #1, the blower had high speed only. Switching the yellow and yellow/black wires resulted in a two speed blower.

Jube · #3 (**permalink**) 04-07-2008, 04:15 PM

Cheers Jim,
Exactly what I was after thanks.

I'll give it a try tomorrow and hope that there's no other problems with the heater system.

Regards,
Julian.

Jube · #4 (**permalink**) 04-08-2008, 05:03 AM

Well I've changed the Blower Motor Switch connectors from the following:

BEFORE: PIN 1 = RED / PIN 4 = YELLOW / PIN 6 = NONE (JUST SOME TAPE) / PIN 8 = YELLOW AND BLACK.

to the following:

AFTER: PIN 1 = YELLOW AND BLACK / PIN 4 = YELLOW / PIN 6 = RED / PIN 8 = BLACK.

....and guess what....no difference except that fuse 3 doesn't blow now.

By the way the red cable which splits off and should then be fitted to the cigarette lighter isn't, as the spade connector has broken off the lighter - this shouldn't make a difference though should it?

Any ideas anyone please as to why the motor isn't spinning up?

Thanks again,
Julian.

**papajam** · #5 (**permalink**) 04-08-2008, 04:18 PM

Using a voltmeter or a test light, confirm power at the red wire. If okay, test for power at the yellow & yellow/black wires at the heaterbox connections while switching from low to high speed. Also check the heater motor earth. If there's both power and earth at the motor, you might try coaxing the motor by spinning the fan with a pencil or similar through the air outlet duct.