1995 No heat or A/C power - nothing works? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**crossy** · 05-23-2006, 01:29 PM

1995 No heat or A/C power - nothing works?
I borrowed a friends complete control panel and tried that but still nothing worked.
I have nothing operational in the HVAC control panel. The one heavy orange wire that runs to the panel does have continuous 12Volts but i cant see where as that wire even has anything to do with the power supply anyway, it dead ends into one of the connectors.
none of the switches or controls get any response.
I checked EVERY fuse in the fuse box and in the underhood relay panel.
I ran a hot wire to several of the connections at the dash and i can hear the electric doors opening and i can get each of the fan speeds??
DAVE

partsman9606 · 05-23-2006, 08:01 PM

sounds like a bad ground possibly

**crossy** · 05-24-2006, 02:09 AM

I wiggled and jiggled everything originally and i still got nothing at all. I'm going to splice into the black ground wire and run a separate ground b/c I already had to repair radio wiring that was mangled and they may have originally shared a common ground wire even though the harnesses are separate. I'll let you know tomorrow evening. Seems i dont havea complete circuit and since i verified power to the controls it only seems logical that the circuit is'nt complete. thanx , DAVE

partsman9606 · 05-24-2006, 08:09 PM

these trucks electrical systems are kind of screwy, if foung thes always have a hot lead to them and the switches break the ground so thats why i suggested that! Danny

**crossy** · 05-25-2006, 12:48 AM

The ground wire was not the issue. Problem continues, There is a power wire leading in that has only 3-5 volts MOST of the time. All of a sudden the voltage will spike up to 12Volts and the control will work and the blower fan will come on?? If you change any of the knob settings it will kick back off and you won’t get it to come back on until ?????. If you leave it alone it will continue to run for however long??? WOW I’m confused . the low voltage is over at the fuse box also so I need to find out where the fuse box gets it power feed from. I suspect something bad in the relay bnox under the hood but i already changed that out and no difference.
DAVE

05-23-2006, 01:29 PM	#1
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	1995 No heat or A/C power - nothing works? 1995 No heat or A/C power - nothing works? I borrowed a friends complete control panel and tried that but still nothing worked. I have nothing operational in the HVAC control panel. The one heavy orange wire that runs to the panel does have continuous 12Volts but i cant see where as that wire even has anything to do with the power supply anyway, it dead ends into one of the connectors. none of the switches or controls get any response. I checked EVERY fuse in the fuse box and in the underhood relay panel. I ran a hot wire to several of the connections at the dash and i can hear the electric doors opening and i can get each of the fan speeds?? DAVE __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks. Last edited by crossy; 05-23-2006 at 05:46 PM.

05-23-2006, 08:01 PM	#2
partsman9606 a country boy can survive Join Date: Jul 2005 Location: Yulee, Fla Posts: 95	Re: 1995 No heat or A/C power - nothing works? sounds like a bad ground possibly __________________ 1991 c/1500 lowered 2/4, 6inch cowl hood 1988 c/1500 plain(girlfriends truck) 1999 chevy tahoe z71

05-24-2006, 02:09 AM	#3
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	Re: 1995 No heat or A/C power - nothing works? I wiggled and jiggled everything originally and i still got nothing at all. I'm going to splice into the black ground wire and run a separate ground b/c I already had to repair radio wiring that was mangled and they may have originally shared a common ground wire even though the harnesses are separate. I'll let you know tomorrow evening. Seems i dont havea complete circuit and since i verified power to the controls it only seems logical that the circuit is'nt complete. thanx , DAVE __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.

05-24-2006, 08:09 PM	#4
partsman9606 a country boy can survive Join Date: Jul 2005 Location: Yulee, Fla Posts: 95	Re: 1995 No heat or A/C power - nothing works? these trucks electrical systems are kind of screwy, if foung thes always have a hot lead to them and the switches break the ground so thats why i suggested that! Danny __________________ 1991 c/1500 lowered 2/4, 6inch cowl hood 1988 c/1500 plain(girlfriends truck) 1999 chevy tahoe z71

05-25-2006, 12:48 AM	#5
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	Re: 1995 No heat or A/C power - nothing works? The ground wire was not the issue. Problem continues, There is a power wire leading in that has only 3-5 volts MOST of the time. All of a sudden the voltage will spike up to 12Volts and the control will work and the blower fan will come on?? If you change any of the knob settings it will kick back off and you won’t get it to come back on until ?????. If you leave it alone it will continue to run for however long??? WOW I’m confused . the low voltage is over at the fuse box also so I need to find out where the fuse box gets it power feed from. I suspect something bad in the relay bnox under the hood but i already changed that out and no difference. DAVE __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.



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