Horn and Blower problems... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

elwood · 12-06-2003, 04:05 AM

I just bought this truck yesterday. It's a '78 with an '85 body.

Problem 1.

The horn does not work, the wire goes from the horn to that junction box on the firewall.

What color wire runs the horn, and is there a relay?

Problem 2.

The blower motor doesn't work with the switch. I noticed that there is no wire hooked to the tab thingy next to the blower motor. What color wire gives it juice? Where's the resistor located?

I'm used to playing with Ford Trucks, so I have to get used to GM stuff.

Thanks for your help!

Russell · 12-06-2003, 05:01 AM

Chances are you need a new column wiring harness, but make sure that you check fuses first! There is a relay for the horn, but it is in different places for every year, so I can't give you a definite answer about where it is. Its attached to the fuse box under the driver side dash for me...

As for the blower motor, check to see if your switch works, if it does, check the blower motor itself.

**old Rusty C10** · 12-06-2003, 12:49 PM

you need a circtu tester to see where the power is to see whats up there

Grim Reaper · 12-06-2003, 05:38 PM

The button often get's screwed up. The actuall horns are just behind the grill in both upper right and left hand corners. The harness.

Look at the colum. You will find a flat plug with 10 or so wires. The black wire on the end or 1 or 2 from the end is the horn. Probe it with a test light. That sould blow the horn when you probe it. Horn blows the problem is in the colum or button.

If the dome light also doesnt work or works funny then you have a blow fuse.

elwood · 12-06-2003, 10:29 PM

I'm going probin'!

jimfulco · 12-07-2003, 05:48 AM

Check the horn fuse.

12-06-2003, 04:05 AM	#1
elwood Keep it gangsta! Join Date: Dec 2003 Location: Peoria, Arizona (Phoenix Area) Posts: 102	Horn and Blower problems... I just bought this truck yesterday. It's a '78 with an '85 body. Problem 1. The horn does not work, the wire goes from the horn to that junction box on the firewall. What color wire runs the horn, and is there a relay? Problem 2. The blower motor doesn't work with the switch. I noticed that there is no wire hooked to the tab thingy next to the blower motor. What color wire gives it juice? Where's the resistor located? I'm used to playing with Ford Trucks, so I have to get used to GM stuff. Thanks for your help! __________________ 1984 K5 Blazer 305-NP208-700R4 Ex Police Unit It's old school, but moves along nicely... '78 C-20 - SOLD

12-06-2003, 05:01 AM	#2
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Chances are you need a new column wiring harness, but make sure that you check fuses first! There is a relay for the horn, but it is in different places for every year, so I can't give you a definite answer about where it is. Its attached to the fuse box under the driver side dash for me... As for the blower motor, check to see if your switch works, if it does, check the blower motor itself. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

12-06-2003, 12:49 PM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	you need a circtu tester to see where the power is to see whats up there __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

12-06-2003, 05:38 PM	#4
Grim Reaper Registered User Join Date: Jul 2001 Location: Atlanta GA Posts: 1,704	The button often get's screwed up. The actuall horns are just behind the grill in both upper right and left hand corners. The harness. Look at the colum. You will find a flat plug with 10 or so wires. The black wire on the end or 1 or 2 from the end is the horn. Probe it with a test light. That sould blow the horn when you probe it. Horn blows the problem is in the colum or button. If the dome light also doesnt work or works funny then you have a blow fuse. __________________ Grim-Reaper 70 Pontiac LeMans Sport Convertible, worlds longest resto in progress Looking for 71-72 2wd Blazer or Jimmy Project

12-06-2003, 10:29 PM	#5
elwood Keep it gangsta! Join Date: Dec 2003 Location: Peoria, Arizona (Phoenix Area) Posts: 102	I'm going probin'! __________________ 1984 K5 Blazer 305-NP208-700R4 Ex Police Unit It's old school, but moves along nicely... '78 C-20 - SOLD

12-07-2003, 05:48 AM	#6
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Check the horn fuse.

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