07 Kenworth T800 AC Fan and Binary Switches

Discussion in 'Kenworth Forum' started by Lowboy456, Apr 21, 2021.

  1. Lowboy456

    Lowboy456 Light Load Member

    Mar 14, 2017
    Thanks for those part numbers. Once I get parts numbers I always write them down in my phone memo for that particular truck.

    Yea I prefer the scales especially dealing with a jug of freon.

    A while back I bought a recovery tank 1st then then later bought a used Appion G5 twin recovery machine like the HVAC guys use but still don't have a way to separate oil out like the really nice 3 to 5000 dollar machines do seen at dealers and garages.
    I would like to have a clear oil separator. I don't see why this clear fuel filter would not do the job.

    I wanted the recovery machine so I could recover the freon, fix the leak or failed part and put the freon back in it without wasting it just to fix something simple.

    Another cool trick I learned before I got the recovery machine and only had the tank is to vacuum the tank down and place it in a bucket of ice and water. Hook up the line, open the valve and it will literally empty an AC system and if its good stuff you can fix the problem and charge it back into the system but not with a badly failed AC compressor. Obviously this wouldn't work at 32 degrees ambient. The vacuum would draw out some but not all of the freon.

    The reason I bought a micron gauge is because of a trick that I learned from the HVAC guys.
    If I vacuum the system down to 250 microns and shut it down, valved off where the gauge still reads, if it rises to 500 microns and rests, there is still moisture in the system. Wow! How cool is that?
    And of course if it keeps climbing there is a leak that's very easy to see with such a fine resolution.
    It did not see the leak in this instance however, my system passed pressure and vacuum test every time but would not hold charge but two days.

    Sea level is 760,000 microns and 0 being a perfect vacuum which I think is unachievable.
    Its saves time. When I see 250 microns on the gauge I know I don't need to go any further with vacuum because that's all I'm going to get. I have seen 240 after valving the vacuum pump out of the mix.

    I never stop learning and each new problem I learn more like in this case. Some leaks and failures or very rapid and easy to find but not this one. I imagine a pro AC guy would have quickly decided a compressor was needed and charged me 1200 to 2000 bucks or something like that to fix it.

    Instead of paying shops fees like that I buy another tool while studying and trying to figure things out myself.
    Last edited: Apr 24, 2021
    Rideandrepair and spsauerland Thank this.
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  3. Lowboy456

    Lowboy456 Light Load Member

    Mar 14, 2017
    The air has worked flawless since I posted this thread. I still have not got a new fan switch because the air is working so well. If I'm on the road the fan very seldom runs.

    The left window regulator went bad with the window all the way down last Friday. Luckily I found one on ebay for 98 bucks it won't be here until this coming Friday though. Raneys and oreilley's are close in price at 244 dollars.

    So I spent Saturday taking the regulator out and propping up the window with a perfectly cut 2x4. I didn't bother putting the old window regulator back in, I don't want to see it again ever.
    Also I blew a tire that same day in the sidewall shortly after the window regulator failed. I've never seen a tire pop like this one it had a very slow leak in the side wall that allowed me to get 25 miles farther and drop my load of gravel.
    When I turned around to back up and dump the load of aggravated base the tire came unseated from the rim.
    So then I cruise 1 hr to a tire shop which was still 50 minutes from home.

    Anyway I was wondering if any of you can get the AC schematic for this truck?
    I assume power goes from fuse to relay through the binary switch to AC compressor

    The fan on this truck is on by default and has to have a ground to the fan solenoid to turn the fan off.
    With the engine off this fan does not free wheel.
    So when the the hi side gets to 320 the fan switch opens and interrupts that ground to the fan solenoid and turns the fan on until the switch closes at

    I assume that's how this works but not positive.
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