The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-30-2018, 05:09 PM   #1
Marshall50
Registered User
 
Join Date: Jan 2018
Location: BRIGHAM CITY, UT
Posts: 2
Heating wiring question

Hey guys, brand new to the forum. I've read many threads but can't seem to find what I'm looking for. Hoping someone can help me out.

I have a 79 K10 with a new 3 speed heater only fan selector. I recently swapped out the heater only box with an ac/heater box that someone donated. I don't care about the ac right now but only want the heater and defroster to work right now. Here's the problem I have... the fan selector is 3 wire and the resistor is 4 wire. First of all is this even possible to use the non a/c selector switch? I don't want to have to buy another new switch just yet unless I know for sure I will want ac in the future. Currently, I only have the blower motor working when the key is on and the selector switch is on hi. There is nothing on the 1st two speeds. Any help is appreciated.
Marshall50 is offline   Reply With Quote
Old 01-30-2018, 06:08 PM   #2
Bandit130
Registered User
 
Bandit130's Avatar
 
Join Date: Dec 2014
Location: Euless, Texas
Posts: 510
Re: Heating wiring question

__________________
1974 Cheyenne 10 LWB Stock 350 W/HEI /TH350/AC/4 BBL Quadrajet


Mopar by Birth
Chevy by Choice
Bandit130 is offline   Reply With Quote
Old 01-30-2018, 06:57 PM   #3
hatzie
Moderator
 
hatzie's Avatar
 
Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,911
Re: Heating wiring question

You can run the non AC resistor and heater control with the heater sub-harness.

AC uses a relay to run the blower at full speed without melting the switch. You'll need to retrofit the AC wiring and relay along with the AC controls.

How are you handling the firewall ducting differences?
__________________
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
hatzie is offline   Reply With Quote
Old 01-30-2018, 07:08 PM   #4
Marshall50
Registered User
 
Join Date: Jan 2018
Location: BRIGHAM CITY, UT
Posts: 2
Re: Heating wiring question

Thanks for your response Hatzie!
That might be a hurdle I have yet to come to. I got the switch to operate correctly. Turn the key on, the blower motor comes on. I also got the blower motor to increase with the selector switch fan speeds respectively. I'm not using the number 4 connector on the resistor. I have hot air but I'm concerned the resistor might heat up to much. Is that possible?
Marshall50 is offline   Reply With Quote
Old 01-30-2018, 07:37 PM   #5
hatzie
Moderator
 
hatzie's Avatar
 
Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,911
Re: Heating wiring question

You should have airflow over it with the blower on. Not sure whether you'll get in trouble without...
__________________
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
hatzie is offline   Reply With Quote
Reply

Bookmarks

Tags
air conditioning, blower motor, heater, resistor, wiring

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:44 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com