my 92 chevy heater/ A/C control module wont turn on. the module is good tested it in buddy's truck. i have power to the module i put test light in plug it lit up. when i put test light on 3 of prongs the heater flaps under dash click and you can here them move. after reviewing the wiring diagram in my haynes manual i have come to conclusion that the ground wire is loose. where would the ground wire be located. i have tried hunting it down no luck. really don't want to pull the dash it i have to i will. i'm a college student ill be doing all work in parking lot. i have decent mechanical skills i'm a black hawk mechanic for military so i can fix it. all help is appreciated. know this is a thread bout my ac i'm wanting to put mild lift on truck for ground clearance. its 2wd so i'm puttin blocks and spring spacers 2in blocks but cant locate shocks that are 2in longer than stock at any auto parts store any one have any knowledge about shocks and where can get decent shocks for fairly cheap. i don't do heavy wheelin just driving through pasture and to deer stand pull trailers lot time need shock that wont squat under weight of trailer

 

screw that. make a ground wire. just run it down the dash and affix it to the base of the instrument panel.

 

so tap in to stock ground wire and run it to chassis and ground it out there

 

yes. cut it from the back of the harness, run an extension down the hole in back there tie it to ones of the screws that connect metal base of the dash to the firewall.

but before you do that, get a DVOMeter and backprobe the harness to make sure you dont have a ground. You should know what color the power is so use the neg. lead and look for the 12V to see if you have ground on the ground wire. If you dont have ground on that wire then cut it and run it to another well known ground source. But keep it clean, there is no pride in sloppy work.

 

what is a DVOMeter? not familiar with this tool. is it same as a mulitmeter? im not best at testing voltage on wires and if has ground or not. correct me if im wrong backprobe the plug on wiring harness and see if there is power to that ground if not cut it and run new line to ground port on firewall and then test it ti make sure its grounded. how do i set up the voltagemeter if thats what im suppose to use and what setting do i put it on i have a Sperry DM-210A its a digital multimeter

 

DVO meter = Digital Volt/Ohm Meter = multimeter.

If you measure for voltage on a grounded line, you will get 0 volts if it is good or you will get ANYTHING ELSE if it is bad. But it could be 0 even if it is bad if there is no voltage present. If you know that it is a valid ground, just run a jumper from that point to any convenient ground (screw) and see if it works.