Keeps shutting off and on

light pilot then turn blower on by thermostat. if it blows it out bad heat exchanger. if it stays lit shut down & pull burner assembly clean pilot orifice.

Some thermostats have a setting that keeps the fan running constantly. If its a programmable one you can change it. If it has a fan limit control it my be sticking.

Blower? Internal house air blower I assume. - Blower relay contacts pitted and stick in on position.
BAD Control BOARD, fault or adjustment program keeping relay energized. Bad emperature sensor not telling Board unit has use up cold air. loose wiring to sensors and board connections

if its a fossil fuel unit meaning nat gas or propane and it lights then goes out in a few seconds try cleaning the flame sensor take out sensor then rub it gently with steel wool then replace should solve problem

INTERTHERM parts can be purchased through a local american supply

it is the heat sequencers. it happens all the time. replace them wire by wire to keep it simple. they are located behind the metal next to the breakers they look like this:

make sure the unit is level or even off a little to the drain side. I have seen this cause this problem several times.

The 55 terminal is marked "herm" it goes to the start winding of the compressor. The 5 terminal is marked "fan" it goes to a wire from the fan motor. The common terminal goes to one side of the power line...The side that is NOT going directly to the compressor.

If your compressor has a starting relay it will have numbers printed on it which can be cross over to a replacement. Some people refer to the contactor as a starting relay. A starting relay will have three terminals on it. Numbered 1-2-5. If there are more terminals on the relay they are just for connections.

your AC have a thermister problem
if u replace the thermister your AC will be OK.