1979 El Camino/ Have an AC question/

[mando13]

Thank you Texas 82, I found out that the original vac.switch was defective so I tried to get a new one but no parts house had it or could get it for me so I went to the junk yard and picked one up.I cleaned it real good and installed it in the control head and after I was done,I turned the AC on and now I get really nice cold air tru all vent doors.What a job but I am glad I'm done with the ac system.
Now,to my next project.The fuel gauge barely shows any gas eventhough I have half a tank of gas.So,I am going to check the gauge itself and the wiring.If all that checks out ok,I am going to check the fuel sending unit.I'm guessing that the sender is inside the gas tank.
I have never replaced one on a G or A body before.It would be nice if there was a access door to get to the sending unit,that way,I will not have to drop the tank but I guess that's asking for too much.
Mando

 

[Longroof79]

Glad to hear that your A/C is functioning like it should. I think the vacuum switches become compromised over time...and like you said, not available anywhere, except used, and even that is a crapshoot. I took a control unit apart on a later GM car, hoping the vacuum switch would be the same or close..but no cigar.
Basically, it's just a small rubber diaphragm...if you can call it that, which diverts the vacuum in order to change the function of the blend doors.

 

[HAFROD]

I would suggest changing the rubber fuel hoses at the sender when you drop the tank. The age of these cars, that rubber is probably pretty dry. If your sender is good, the sock (tank strainer) is still available at your dealer. My strainer had split. It was under $20

 

[Texas82GP]

Thank you Texas 82, I found out that the original vac.switch was defective so I tried to get a new one but no parts house had it or could get it for me so I went to the junk yard and picked one up.I cleaned it real good and installed it in the control head and after I was done,I turned the AC on and now I get really nice cold air tru all vent doors.What a job but I am glad I'm done with the ac system.
Now,to my next project.The fuel gauge barely shows any gas eventhough I have half a tank of gas.So,I am going to check the gauge itself and the wiring.If all that checks out ok,I am going to check the fuel sending unit.I'm guessing that the sender is inside the gas tank.
I have never replaced one on a G or A body before.It would be nice if there was a access door to get to the sending unit,that way,I will not have to drop the tank but I guess that's asking for too much.
Mando

The fuel level sender is in the tank. Once you have the tank down you can check the sender with an ohm meter. I agree with you completely that there should be an access door. Sometimes I wish the engineers and accountants would think of the guys who have to fix the cars a little more when they decide against something like an access door for the fuel sender. All cars should have one, especially modern ones with the fuel pump in the tank.

 

[mando13]

Thanks to all of you for your help. I will be droping the gas tank tomorrow to check the sending unit.I'm almost sure that's the problem.
Before I buy one,I'm going to do some testing on that unit.Correct me if I am wrong.When the arm is all the way up (Full) mode,I should get a reading of about 4 to 6 ohms.When the arm is all the way down,(empty) I should get a high resistance of about 100 to 105 ohms.
Am I correct or am I way off? What is your method of testing the sending unit? The price on a new sending unit is about 80 to 90 dollars.
Mando

 

[HAFROD]

I can't remember the ohm ranges. I think I found that in a search here or google. I took mine apart and cleaned the slide with scotch brite. It started working after that.

 

[ssn696]

Wow. Not found on RockAuto.com. That's a first. I checked out Spectra and Dorman. Also no dice. When I flip to 1984, only GM comes up, and over $100. Try cleaning yours as described above. Look for breaks in the winding. Monte Carlo senders are still available new, so consider that as an option.

 

[mando13]

Thanks for your suggestion. I have a question? I found the sending unit at OPGI for $85.00 but before I order the part,I want to make sure that the problem is the sending unit and not the gauge.This is what happens with the gauge.If I disconnect the wire that goes to the sending unit,I turn the key on,the gauge needle moves all the way to past full.I than reconnect the wire to the sending unit and turn the key on, gauge needle moves all the way back to empty.So,this looks like the gauge itself is ok,right? Let me know what you think about this scenari😵nce I know for sure that the sending unit is bad for sure,I will place the order from OPGI.Thanks Again.
Mando