What are these things? Overhead heat/air system!

[Woodhook]

I will add 2 photos that will show my problem. The small wire connected to that block, comes from the air conditioner and then goes through the firewall and connects to these two resistors/relays/fuses, (whatever they are) above the brake pedal. I've already installed a new wiring harness and it doesn't show any connection to these two resistor things. I don't have a degree in electrical engineering nor have I ever worked for NASA. If I do indeed need to use these two resistor things, how do I correctly power them up? I love my square body and hope to be buried in it someday but sometimes I think Moe and Larry must have been engineers at GM at some point!!

 

[Strick]

The pic on the left has an aftermarket circuit breaker added into the system and bolted to the firewall. The second pic is a switch of some sort on the brake/clutch pedal assembly. I don't know exactly what that because it's not for cruise control or the park/neutral safety switch.

Strickland

 

[Keith Seymore]

I don't remember Moe but this guy was kinda dodgy.

K

You must be registered for see images attach

 

[Woodhook]

The little relay/breaker hanging down on the left picture is actually the same silver relay/breaker in the right picture, installed under the dash. I'm going to remove the heater/ac control and see if the ends of these wires would connect to the fan switch. I'm sure I'm going to have to connect some of these wires to 12v in order to power the blower motor. FYI, the picture on the right is before I started the removal, left one is me trying to figure out where everything goes.

 

[Woodhook]

I went inside the truck and removed the other relay/breaker and I plugged both of them in the wiring harness where they go. The little wire on the right is the one that connects to the engine side of the firewall. The rest of these are inside the cab. The two ends of this wiring harness are identical! Even the wires are the same colors. I've checked the fan switch, wiper switch, light switch, and I can't find any connector that would even accept these ends. Could this be something GM installed for other models that might have electric windows, door locks, cruise control, etc. Any help would be appreciated!!

 

[Woodhook]

I’ve searched the light duty truck service manual and I think this is the wiring harness for the overhead heat/air unit in suburban models. It makes sense that the 3 connectors on one end of that harness pictured are exactly the same as the other end. The overhead unit has two blower motors which are feed by the two ends. I’m not sure why my truck was ever wired this way.

 

[bucket]

Are you sure it's not a power lock relay? Is this a truck or Suburban?

 

[Woodhook]

It’s a truck. The vin plate on the door jam is hard to read. I’ve looked at my insurance papers and tried to search for the correct data, but nothing will come up. I can see the words “camper loading data” on the plate, not sure if that is on all the square bodies. One other thing I found out is the front differential is corporate. I had some trouble finding the correct chrome cover and gasket. Is there any other place to find the vin?

 

[Gilmore]

The second set of wires in your photo string of 4 photos is your electric door harness and relay. Do not throw them away unless you are upgrading.

 

[Woodhook]

My truck don’t have any power to the doors, but maybe it was wired for it. I’ll hang on to the harness but I’m not planning on using it. Thanks,

 

[Mr Clean]