A/C Evaporator temp switch?

The place to discuss problems and routine maintenance questions and tips that are NOT specifically diesel-related.
racertjay
Regular Member
Posts: 4
Joined: Wed Jun 12, 2019 4:54 pm
Location: Mississippi
Isuzu vehicle(s): 1993 Space cab 2.6

A/C Evaporator temp switch?

Postby racertjay » Wed Jun 12, 2019 6:18 pm

Hello guys, first time poster, long time lurker, been very helpful in fixing a couple problems in the past, (THANKS A LOT) but this one I can't seem to find much on.

My problem with my 1993 Isuzu SpaceCab 2.6L Manual. R134 from factory. Here recently my A/C compressor has been short cycling, and rapidly at times (gauges have normal psi , 30-35 low and 230-250 high, it's upper 80s in south MS). I jumped the pressure switch on the drier and saw same results, so it must be good. Next I moved to the Evaporator Temperature sensor. Is there a way to diagnose it? There are 3 wires in the plug. It is labeled + - L the part number on the side is ZEXEL 582550-5900 3.5 deg C. I can't seem to find the part either. Is there a way to test, bypass or jump the sensor to ensure it is good/bad? Or is there a relay i may be missing that could be causing the short cycling? Thanks for the help in advanced.
1993 Isuzu SpaceCab 2.6L 5-speed 2x4

dorf
Regular Member
Posts: 387
Joined: Sun Jul 17, 2011 1:03 pm
Location: N. Central Arkansas 81 LUV 4x4

Re: A/C Evaporator temp switch?

Postby dorf » Thu Jun 13, 2019 2:02 pm

Sounds like over serviced....or under serviced


Can you move the temp probe to another location in evaporator

Mine has a ...iinc. dec knob to adjust temp when compressor kicks in

User avatar
JoeIsuzu
Site Admin
Posts: 20636
Joined: Thu Aug 19, 2004 9:11 am
Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Re: A/C Evaporator temp switch?

Postby JoeIsuzu » Thu Jun 13, 2019 3:30 pm

TJ--
Are you in north MS? Hope you will get around to an intro soon.

Jack

User avatar
JoeIsuzu
Site Admin
Posts: 20636
Joined: Thu Aug 19, 2004 9:11 am
Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Re: A/C Evaporator temp switch?

Postby JoeIsuzu » Thu Jun 13, 2019 11:43 pm


racertjay
Regular Member
Posts: 4
Joined: Wed Jun 12, 2019 4:54 pm
Location: Mississippi
Isuzu vehicle(s): 1993 Space cab 2.6

Re: A/C Evaporator temp switch?

Postby racertjay » Sun Aug 11, 2019 4:20 pm

So I have confirmed it is a bad thermo switch that is bad causing the relay to short cycle. After using a volt meter I determined the switch connects the Ground to/ from the Relay, so I by passed the switch by connecting the "-" (negative 12v) and the "L" terminals together. It turns the relay and compressor on and I ran it for a week with no short cycled relay/compressor, but I noticed in the low fan setting after a while, the temp of the air would slowly increase in temperature (I'm guessing because the condenser was freezing up). So I'm assuming I do need this Thermostat switch. I ordered this one off ebay bc I thought it was pretty close but it won't work https://www.ebay.com/itm/Zexel-thermose ... 2749.l2649 I cant seem to find an exact part number new part, or even a used one for that matter. Does anyone have a donor/parts truck and would sell me one?
1993 Isuzu SpaceCab 2.6L 5-speed 2x4

racertjay
Regular Member
Posts: 4
Joined: Wed Jun 12, 2019 4:54 pm
Location: Mississippi
Isuzu vehicle(s): 1993 Space cab 2.6

Re: A/C Evaporator temp switch?

Postby racertjay » Sat Aug 24, 2019 8:03 pm

Got a new switch from user JLEMOND and everything is working back to normal again. Constant ice cold AC with no freeze ups!
1993 Isuzu SpaceCab 2.6L 5-speed 2x4