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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: xtremjeepn on March 19, 2008, 11:14:14 am

Title: Heater wiring diagram? HELP!!
Post by: xtremjeepn on March 19, 2008, 11:14:14 am

So I totally rewired my crew cab project wtih a "Painless Wiring" harness. (most of the original wiring was simply missing when I got the truck shell.


Here is all Painless has to say in there instructions for the wiring of the heater.

Quote

Heat Only
8.9.1 Units with heat only will connect wires brn #904 and brn/wht #967 together in
AC Section A using a blue 1/4" push on connector. Attach as per Diagram
#9.
Note: The tan wire #969 will be omitted at the switch and the
resistor. Tape and stow away. The grn wire #902 will also be
omitted in Engine Section B and in AC Section B, because there
is no compressor. Tape and stow away.

I've done that and still have no functioning fan/blower. (my truck is heat only no A/C)

There is a group of wires labled for the heater blower wtih a plug for an A/C blower relay. (which I don't have because I have heat only).

They don't give any sort of schematic for this at all.  I have no idea what to test/splice etc.

NONE of the wires going to the heater or the extra set have power going to them at all. (key on). I need to figure out which wires should have power and where do they get it from?

If I add the A/C relay will this power the system? (Is this relay something the local autoparts store should have?)

Thanks.

Title: Re: Heater wiring diagram? HELP!!
Post by: JJSZABO on March 19, 2008, 02:41:11 pm

A/C relay will not work with heat only.

I just finished with my Painless GM Universal truck harness install.  I also have heat only.  I used the existing wiring harness from the fan switch to the three prong resistor then a single black wire to the blower.  You should have a brown wire from the fuse panel to the fan switch - this wire should have 12v with the key on, does it?  This is the only wire you need from the painless system if you use your stock heater control wiring.

The A/C control wire of mine, I just tapped and stowed away.

I can take pictures of mine if it would help.

Title: Re: Heater wiring diagram? HELP!!
Post by: joesgarage71 on March 19, 2008, 11:12:06 pm

Cole,
 email me and I'll scan a diagram and send it back, What year?
 Steve

Title: Re: Heater wiring diagram? HELP!!
Post by: joesgarage71 on March 20, 2008, 12:49:33 pm

 Cole,
 I sent two to your email, I will send some more later.
 Steve

Edit: I just tryed to send you two emails and they were not delivered because of size.

Title: Re: Heater wiring diagram? HELP!!
Post by: xtremjeepn on March 20, 2008, 03:32:51 pm

Try RS4Wolf   [AT] Gmail 

Title: Re: Heater wiring diagram? HELP!!
Post by: joesgarage71 on March 20, 2008, 07:41:30 pm

 Coming at ya, 4 pages.

Title: Re: Heater wiring diagram? HELP!!
Post by: xtremjeepn on March 20, 2008, 09:19:13 pm

Thank you very much.  Have not had a chance to look at them but it looks like that will help a lot.

Title: Re: Heater wiring diagram? HELP!!
Post by: joesgarage71 on March 22, 2008, 03:13:05 pm

 Your welcome, anytime.