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 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-21-2007, 06:26 PM   #1
Jwill41
Registered User
 
Jwill41's Avatar
 
Join Date: Aug 2002
Location: Farmers Branch, Tx
Posts: 1,009
heater blower speeds

I just bought a 69 and have a question about the fan. It works ok on low and medium speeds but slows down when put on high. This is a factory a/c truck and i am trying to get some bugs out of it so I can stay cool this summer. Help me!
__________________
http://www.picturetrail.com/jwill41

67 1/2 ton GMC short step side
68 1/2 ton Chevy long fleet side
72 1/2 ton Chevy Suburban
99 1/2 ton Chevy Suburban

founder (and only member) of the primer/clearcoat club
Jwill41 is offline   Reply With Quote
Old 06-21-2007, 08:11 PM   #2
raws67
Registered User
 
raws67's Avatar
 
Join Date: Jun 2007
Location: lemoore ca
Posts: 126
Re: heater blower speeds

I just had the same problem! My hi fan wouldnt even run, believe it or not it was a bad posative battery wire. I replaced the posative wire and the smaller gauge wire that hooks in up close to the battery and everything works great now, crazy thing is the only thing I noticed the whole time was the hi speed fan not working.
raws67 is offline   Reply With Quote
Old 06-21-2007, 09:24 PM   #3
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
Re: heater blower speeds

more likely, it is the hi speed relay under the dash towards the glove box.
Longhorn Man is offline   Reply With Quote
Old 06-21-2007, 10:12 PM   #4
Jwill41
Registered User
 
Jwill41's Avatar
 
Join Date: Aug 2002
Location: Farmers Branch, Tx
Posts: 1,009
Re: heater blower speeds

Quote:
believe it or not it was a bad posative battery wire
I checked all the connections under the dash and under the hood.Everything looked good.

Quote:
more likely, it is the hi speed relay under the dash towards the glove box
Where is this "high speed relay" and what does it look like?
__________________
http://www.picturetrail.com/jwill41

67 1/2 ton GMC short step side
68 1/2 ton Chevy long fleet side
72 1/2 ton Chevy Suburban
99 1/2 ton Chevy Suburban

founder (and only member) of the primer/clearcoat club
Jwill41 is offline   Reply With Quote
Old 06-21-2007, 10:15 PM   #5
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
Re: heater blower speeds

someone will have a pic... it looks a lot like the horn relay by the fuse box, silver metal deal with a plug on the bottom. it should be under the dash by the glove box.
Longhorn Man is offline   Reply With Quote
Old 06-21-2007, 10:25 PM   #6
SkylineNXS
Registered User
 
SkylineNXS's Avatar
 
Join Date: Oct 2006
Location: Elgin, IL
Posts: 658
Re: heater blower speeds

My fan was horrible, it would barely turn on even iff u kicked it all the way to high speed. The problem with mine was the bearing for the motor shaft was horribly worn, so i needed a new fan, but urs sounds much less severe. If u cant find the problem, possibly the relay like stated above, i would maybe take out the fan and check.....of course its really not too fun to remove, so i would try anything and everything else first...

Brad
__________________
2000 GMC Sierra EXT Cab Short 4x4, finally mine...

1966 C10 SWB Fleet, 250 I6, three on the tree....

Previously Owned....
1987 Chevy R10 "Silverado" (at least the badges were) Short Step 350 700r4....

1972 Chevy LWB Fleet 350/350






EXTENDED CAB ALL THE WAY!

.._..~...-...._...____
.._..-...______|_|__\____
..-..~.|_(O)__|_|__|_(O)]
SkylineNXS is offline   Reply With Quote
Old 06-21-2007, 10:29 PM   #7
wibilly
Senior Member
 
wibilly's Avatar
 
Join Date: Nov 2005
Location: northwestern wi
Posts: 2,111
Re: heater blower speeds

it is in the farthest to the right side of the under dash hvac box directly below the right side of the glove box held on by 2 5/16 head screws
__________________
common sense isn't so common anymore
wibilly is offline   Reply With Quote
Old 06-21-2007, 10:33 PM   #8
paaw
Registered User
 
paaw's Avatar
 
Join Date: Feb 2006
Location: nashville
Posts: 217
Re: heater blower speeds

please let me know if you get this fixed, have the same problem when i put it on high seems like it goes back to low. Have an ac truck too.

chico
__________________
1997 pontiac grand prix gt (daily driver) for now; 2004 dodge ram quad cab (wife's truck) 4.7; 2000 pontiac booneville (wife daily driver) 1972 chevy cheyenne 350 bored 40 over 700r trans 373 gears ( posi) soon to be daily driver; 2002 gsxr750 sold
paaw is offline   Reply With Quote
Old 06-21-2007, 11:06 PM   #9
Jwill41
Registered User
 
Jwill41's Avatar
 
Join Date: Aug 2002
Location: Farmers Branch, Tx
Posts: 1,009
Re: heater blower speeds

Thanks all. I saw that relay yesterday. It looked just like a horn relay. Is there an easy way to test it or should I just buy a new one?
__________________
http://www.picturetrail.com/jwill41

67 1/2 ton GMC short step side
68 1/2 ton Chevy long fleet side
72 1/2 ton Chevy Suburban
99 1/2 ton Chevy Suburban

founder (and only member) of the primer/clearcoat club
Jwill41 is offline   Reply With Quote
Old 06-22-2007, 03:20 AM   #10
GMC Jim
Senior Member
 
GMC Jim's Avatar
 
Join Date: Dec 2002
Location: Portland, Oregon
Posts: 901
Re: heater blower speeds

The relay case needs to be grounded..... remove relay, remove rust. corrosion and remount with some star washers that will bite into the relay as it is replaced on the firewall, Also check wire connections to the relay
__________________
'71 GMC;fleetside;PB/PS/AC/CC/402 Eng./Custom Paint/110,000act miles/3 fuel tanks(52gal).

Last edited by GMC Jim; 06-22-2007 at 03:22 AM.
GMC Jim is offline   Reply With Quote
Reply

Bookmarks


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 10:09 AM.


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