4020 stolpher cab with A/C intermittent ??

Jdtractorman123 · Apr 10, 2018

I have a 1970 4020 console with stopper cab and yes a A/C still on R12. Blows super cold but now the fan in cab quit and also the compressor stopped turning. Cut the switch off while tractor is still running and let it sit and it come son again blowing cold for less,than a minute and turns back off.... I check outside and lines are not froze up. Is there a relay or temp switch possibly going out telling it to turn off or a ,aim relay for all of it since the blower fan don't work either ..?
Thanks,
Shawn

Bob · Apr 10, 2018

Sounds like a weak circuit breaker, or loose or corroded terminals at a circuit breaker.

Remove load and breaker cools and resets.

Could be a loose connection somewhere else, or an intermittent short that pops the circuit breaker.

Possibility it's a failing "cab relay", but the way it's acting the first scenarios seem more likely. Could even be the clutch coil or a fan motor drawing excess current and tripping a breaker.

I'm not sure how well the factory manual covers those components and where they are located, or how many variations there may be, and mine's at the shop, 25 miles away at the moment.

I would start by taking off the cowl and the LH sidecover of the control support and check for loose connections, and look for any signs of heat damage to wire terminals.

With a test light, check both sides of each breaker for power, should be able to find the one that's tripped.

If you listen carefully you may be able to HEAR a breaker trip or reset when load is removed.

fdt860 · Apr 11, 2018

There is a specific workshop manual for the AC system.

Tx Jim · Apr 11, 2018

Ditto what Bob stated about circuit breakers. It appears there are 2 circuit breakers(key 13)

Jdtractorman123 · Apr 11, 2018

Thanks for the tips guys! I'll check the relays and report back.

larryanderson · Apr 11, 2018

Keeping a 48 year old A/C unit is challenging.Circuit breakers and connections are the usual problem.Its almost easier to replace them all .I bought 4 1972 4020 from Nebraska with factory Hinsen cab w/A/C and was shocked when they all worked.The newer systems are much better but they fail for same reasons some times.

4020 stolpher cab with A/C intermittent ??

Jdtractorman123

Member

Bob

Well-known Member

fdt860

Well-known Member

Tx Jim

Well-known Member

Jdtractorman123

Member

larryanderson

Well-known Member

Similar threads