Power Ram 250 C

I just got my hose back today for my air conditioner on my 92 dodge diesel truck and I starting to cut the hose to fit in the new one and before I knew it I was cutting through the little temperature probe that goes into the big a/c hose mounted on the firewall. Now my question is does any one know where I can find the little plastic box with wires and a probe on one end and wires and the plug on the other? I'm not sure what the probe tells the truck but I'm sure I'm going to need it in order for the a/c to work properly.

Jim Lane

If it is the same as the one on my 1991 (No ECM) they have them at your Dodge dealer.
I bypassed mine with a relay about 3 years ago.
Jim

Temp Sensing Switch P.N.#56005783 (mounted on H block) $64.88 (takes 1 day to get.)

Power Ram 250 C

Could you tell me what you mean by bypassing it. Did you eliminate the original box and probe? Thanks.

Rampage1967

Don't do that, that sensor keeps the evaporator from freezing up.
It regulates evaporator temp to just above freezing.

Jim Lane

Here is a link to the writeup I did on this modification last year.
https://www.dieseltruckresource.com/...d.php?t=112028



The only downside I have found to this modification is that I have a miserably cold air conditioner, this is with the blower setting on the medium speed and I was cruising on the freeway.

Whenever my family is in my truck they are always covering up with a jacket even in the heat of summer.

Yes this switch is supposed to prevent the evaporator from freezing up but if you look back at all of the systems since the 1950’s they all survived without them, it was not until the auto manufactures felt they had to think for the operator.

All of my vehicles have always had killer super cold air conditioners in them because I would make modifications to them in one way or another.
Back in the 70’s I had a Mustang that got so cold it would blow ice slush at you through the vents.

Disclaimer:
I am not saying this will make yours colder because this is only to eliminate the cycling switch that failed but if your system is in good working you might see lower temperatures, if the air seems to diminish or warm up then cycle it to vent for a few minuets to thaw it out then you are back in business. Also keeping the blower off LOW will prevent ice ups.
Jim

92DuallyCTD

Hey Jim Lane, that's really COOL(pun intended ...), but only lasts for a little while, eh? After a few minutes at that temp, there should be one huge ice cube forming on the evaporator, cutting off airflow and eventually running warm, right? Unless you live in near-zero humidity, it doesn't stay 20deg long(though I wish mine would - usually hovers around 38-40deg). Kansas City and the like just has too dang much humidity year-round for my liking!! :-)

Power Ram 250 C

That is some cold air conditioning!!!!!! I think I will check my local junk yards first and then come back to this plan of action if the other option fails.

Jim Lane

Ice up? It has only iced up maybe 4 times since I have made the modification, my AC runs flawlessly freezing.
I usually drive with the A/C blower on no lower than medium speed. My register temps are usually around 35*- 40* tempered and my cab is always cold even when it is getting into the 100* temps outside.
My wife and daughter are always telling me to turn it off because it is too cold in my truck and are always covered up or wearing a jacket.
Keeping the cool inside is also helped because I have a well-insulated cab, I pulled the carpets and insulated the floor pan with 1/2" foil backed foam core then I have 5/8 foam carpet padding and then I put the carpet back down. I did this behind the seat and also up as far as I could go up the firewall. I was doing this for soundproofing. I also pulled my door panels and have 5/8 padding behind them. This alone cut down on a lot of outside noise.

I noticed that I can leave a bottle of Dr.Pepper on the floorboard at night and then get into the truck around 2:00 P.M. the next day after all of the heat soak and the bottle is still cool to drink.

The only time I remember that I was not happy with my AC is when I was going to Las Vegas in July several years ago, I stopped in Baker CA. to get a A&W and the big thermometer read 124*..
I should have left the truck running and I should of had a high idle control.
I live in Southern California as far as the humidity.
Jim

Power Ram 250 C

Did you leave the probe and little plastic box with the 5 wires coming out of it on the line but just don't used it anymore?

Jim Lane

No I removed it when I was trying to see if I could repair it, I removed the potting from the circuit board to see how it worked I was going to see if I could replace the dip relay with an external one.
I capped the well in the suction line for further use and the probe and box are in the garage.
Jim

Power Ram 250 C

One more quick ? How do get your personal information under what you type everytime. I've looked in about everything but no luck on finding out how to put it in.

Jim Lane

Are you refering to your signature?
It is in the User CP.

Power Ram 250 C

Okay, thank you. I've must have jumped over that a few times and didn't even know it.

Power Ram 250 C

Well, I ended up finding a used hose that was in good condition. Put everything together with new gaskets. Took it to a local repair man and he charged up the line, lucky found no leaks but the a/c pump would no come on. He got to looking around and I think he said a wire running along the firewall that goes from a plug on the drivers side to the passengers side where the a/c hoses hook in. We got that hooked up and the compressor cycled and the air got cold. So for now I think my A/C problem is history. Thanks again for all the input.

Jim Lane

Sounds great..
What did you do about the cycling switch? did that come with the line?
Also how much did they charge you to replace the freon? was it R-12 or R-134?
Jim