heater problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mr.Supersonic · 12-23-2016, 08:17 PM

i'm sure a million people have had this same problem, and if someone could post a link that would be awesome too.

i have a 1970 c20 that i just pulled from a barn. everything seems to work except the heater. nothing turns on, no fan, no nothing. I know that the heater box under the dash is in disrepair, as it has baling wire holding it together.

it might be a wiring problem, but i'm not sure. any help would be great.

custom10nut · 12-24-2016, 12:26 AM

It's most likely corrosion on the wire connections. The fan motor is easy the get to and remove, from under the hood. You have to take the passenger side hood hinge loose (or take the hood off all together), put your test leads on and test it with a battery. If the motor is good, and all your connections are clean, then you do have a wiring issue. Use a test light and Ohm meter to check contnuity before you tear out any wiring.

Toms67 · 12-24-2016, 05:26 AM

If you pulled it from a barn chances are little critters called Mice made it home. I wouldn't be surprised if that is the case with you. If you pull the fan motor off. And look inside. You can tell if they've been there. Pretty nasty mess. Hope not for your sake. Good luck.

Mr.Supersonic · 12-24-2016, 09:58 AM

Quote:

Originally Posted by Toms67

If you pulled it from a barn chances are little critters called Mice made it home. I wouldn't be surprised if that is the case with you. If you pull the fan motor off. And look inside. You can tell if they've been there. Pretty nasty mess. Hope not for your sake. Good luck.

Oh man I hope that mine doesn't look like that! It hope it is wiring, I've had wiring problems with this truck before. Thanks for the advice!

Andy4639 · 12-24-2016, 10:40 AM

Take the 2 screws out of the bottom of the dash holding the controller in. Pull it out and see if the harness is connected. Is take the fan switch off the middle lever off 1/4" socket and take it a part with a small screw driver. Clean the brass with a brush and all the contact points. Put it back together and make sure you have the harness hooked up at the fuse block. Mine works on all speed now. I just did this Thursday.

F.A.A.benny · 12-24-2016, 11:15 AM

Quote:

Originally Posted by Toms67

If you pulled it from a barn chances are little critters called Mice made it home. I wouldn't be surprised if that is the case with you. If you pull the fan motor off. And look inside. You can tell if they've been there. Pretty nasty mess. Hope not for your sake. Good luck.

Gotta love that smell..Ive had to scrap heater boxes because even after cleaning it really well, bead blasting, and painting the inside, the smell was still there

Toms67 · 12-24-2016, 11:18 AM

That was the case with my heater box. It even rusted out all the metal inside. They do a lot of damage. Luckily they didn't get my wiring.

12-23-2016, 08:17 PM	#1
Mr.Supersonic Registered User Join Date: Aug 2016 Location: peabody ks Posts: 27	heater problems i'm sure a million people have had this same problem, and if someone could post a link that would be awesome too. i have a 1970 c20 that i just pulled from a barn. everything seems to work except the heater. nothing turns on, no fan, no nothing. I know that the heater box under the dash is in disrepair, as it has baling wire holding it together. it might be a wiring problem, but i'm not sure. any help would be great.

12-24-2016, 12:26 AM	#2
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,883	Re: heater problems It's most likely corrosion on the wire connections. The fan motor is easy the get to and remove, from under the hood. You have to take the passenger side hood hinge loose (or take the hood off all together), put your test leads on and test it with a battery. If the motor is good, and all your connections are clean, then you do have a wiring issue. Use a test light and Ohm meter to check contnuity before you tear out any wiring.

12-24-2016, 05:26 AM	#3
Toms67 Registered User Join Date: May 2016 Location: Sackets harbor ny Posts: 282	Re: heater problems If you pulled it from a barn chances are little critters called Mice made it home. I wouldn't be surprised if that is the case with you. If you pull the fan motor off. And look inside. You can tell if they've been there. Pretty nasty mess. Hope not for your sake. Good luck. Attached Images

12-24-2016, 10:40 AM	#5
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: heater problems Take the 2 screws out of the bottom of the dash holding the controller in. Pull it out and see if the harness is connected. Is take the fan switch off the middle lever off 1/4" socket and take it a part with a small screw driver. Clean the brass with a brush and all the contact points. Put it back together and make sure you have the harness hooked up at the fuse block. Mine works on all speed now. I just did this Thursday. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

12-24-2016, 11:18 AM	#7
Toms67 Registered User Join Date: May 2016 Location: Sackets harbor ny Posts: 282	Re: heater problems That was the case with my heater box. It even rusted out all the metal inside. They do a lot of damage. Luckily they didn't get my wiring.



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