Thermo king tripac apu

The ac ran before, last time was last year.
This is a 2008 Thermo King unit
(with the kill switch on, motor won't start, on mine the motor runs with the fan and heater, it shuts off when ac is selected).

we vacuumed the system and recharged it again.
we tighten the belt
we changed the binary pressure switch (is thee only one pressure switch on this system)
all fuses are ok
need to check the fan on the condenser, propelled turning by hand, not checked with batery
anything else i check?
Ty all

 

Check the wiring at the binary switch to be certain it is working. That is a trouble spot, and they changed the design of the switch a few times.

 

The condenser fan should come on before the unit even starts when it is in AC mode. If it doesn't, check that a test light on the harness lights up when you turn it on AC mode.

My guess is that you have a bad condenser fan.

 

There should also be a low pressure cutout on the evaporator unless the high psi switch style you have does both.

Check the new switch you just got with an ohmeter (unscrew it from the port). If it's closed with no pressure on it, then there should be a low pressure cutout in the system.

If it's open, the switch performs both functions. Check to make sure the switch closes after you screw it back on to the port.

 

Ok, Thanx for clearing. i checked it before installing it, and it was open, closes the contact as soon as i instal it. ( on evaporator site, is no other switch and nowhere else).
The ac does not come on, neither the fan blade outside at the condenser. If fan is bad ac won't start?
at this point i have either the ac not engaging, bad part or bad fan.
We recharged the system after doing vacuum.
TY

 

new switch

 

i think i remember in the past something about the fan coming on for a few seconds even if the system will shut down by it self due to malfunction.
this is the first thing i will check tomorrow.

 

With certain inverters you have to power off, then power on while pressing the reset button at the same time to get it to work. You only have a small window to push in that reset button while powering it on.