AC compressor won't run, tried new cap, 83 VAC at terminals

This will do it for now, a human controlled relay, I enjoy cold air! Until the new part arrives.

A couple of things to check- ground the yellow control wire to make sure the box is getting the right signal. Also disconnect the blue plug to the freeze control- a bad one would keep the compressor from running.

And- across the capacitors is not the place to check voltage.

So your control board is bad

I am thinking if I should bypass this sticky relay with a manual on/off switch while the new analog control box would arrive. It's going to be 100F for the next two days here in San Diego.

On the last picture, you can see that I am touching the FAN terminal with the red lead. And you can also see the two black wires of the SPP6 in the bottom right of the picture are connected to the HERM and C leads.

Actually I think I figured it out to be a K4 relay in the analog control box.

I opened it up, and see the black square box with a blue and black wire in the middle:

When I shorten these two wires (I used my pliers and the sparks burned the terminals a little), the compressor started to run!

j-d wrote:
Ya Know, it looks from the upper picture, showing the SPP6 connected, that it isn't hooked up correctly. I say that because BROWN is on FAN in the pic where I can see the stamping on the RUN Capacitor. It needs to be across HERM and COMMON. If you're still trying to start it with one terminal of the SSP6 on FAN, the SPP6 is either Not Helping or actually Interfering.

Same here. You don't have it on the right terminals needs to be on herm or comp and common cap should be on white and red not brown . . . Brown is fan

Ya Know, it looks from the upper picture, showing the SPP6 connected, that it isn't hooked up correctly. I say that because BROWN is on FAN in the pic where I can see the stamping on the RUN Capacitor. It needs to be across HERM and COMMON. If you're still trying to start it with one terminal of the SSP6 on FAN, the SPP6 is either Not Helping or actually Interfering.

If the cap is the same as line voltage, you have a bad connection. Use the voltmeter to verify you have 115 volts to the trailer, plug into any receptacle. Turn on the AC, does the voltage drop? If yes, check the incoming line connections in the panel, clean and tighten. If no, check the line at the compressor, low voltage, check the connections at both sides of the breaker, throw it off-on a few times, recheck. Best guess, one of the above will fix it.

WDP

My guess, and my guess is based on working on a few of these, is that the capacitor you're probing in the pic is bad.
That's the "RUN" Capacitor for both the Compressor and the Fan. The Fan runs so that half of the Run Capacitor is good. Terminals are probably marked FAN (which shows in the pic, brown wire on it), HERM or COMP (for Hermetically Sealed Compressor) and COM for Common which usually is not marked.
Did you wire the SPP6 correctly? It should simply go across the Compressor Run Cap which would be HERM and COM. But if the HERM section of the RUN Capacitor is bad, Compressor still will not start. Should start on Shore Power with a good Start Capacitor (like you SPP6) or without one, but MUST have a good RUN Cap.