Relay testing

[T_Diesel]

Is there a simple way to test if a relay switch is working properly?

My aircon is playing up and i'm pretty certain that the relay is not switching 100% of the time when I turn the A/C on.

[-Scott-]

Is there a simple way to test if a relay switch is working properly?

My aircon is playing up and i'm pretty certain that the relay is not switching 100% of the time when I turn the A/C on.

A "relay switch"? Do you mean relay, or a switch?

An intermittent problem is probably the hardest type to troubleshoot.

If it's a relay, identify the coil connections and apply power. Does it click?

Do the contacts show good continuity (low resistance) when closed? Is the low resistance a repeatable reading, or is it slightly different every time you operate the relay? This could indicate dirty contacts. You could use a similar test for a switch, too.

FWIW, I had trouble with an A/C relay not switching on the condenser fan when it should. On the bench, it tested fine - even pulled it apart to look for a problem. Swap it with an identical relay in another position, and the fault followed the relay - whichever position the relay was in, that function wouldn't work.

Dealer wanted over $100 for a replacement - a $15 replacement from a wrecker did the trick.

[T_Diesel]

I mean the actual relay itself. I can not hear the relay clicking on when I put the A/C switch on inside the cabin. Fuses are all ok, tested the compressor and that is fine aswell so must be the circuit failing somewhere between the cabin switch and compressor.

Checking the relay was going to be my next trouble shoot.

Any other ideas on what it could be?

[chimpboy]

A/C pressure switch? Could try jumping across it (briefly) to see if this engages the compressor clutch.

[T_Diesel]

A/C pressure switch? Could try jumping across it (briefly) to see if this engages the compressor clutch.

Already done that, and it engaged.

[-Scott-]

A/C pressure switch? Could try jumping across it (briefly) to see if this engages the compressor clutch.

Already done that, and it engaged.

Isn't that your problem, then? Switch is closed when pressure is adequate. If shorting the switch engaged the clutch doesn't that mean the switch isn't closed when you want it to be? Which tells me you're low on gas.

What am I missing?

[chimpboy]

A/C pressure switch? Could try jumping across it (briefly) to see if this engages the compressor clutch.

Already done that, and it engaged.

Isn't that your problem, then? Switch is closed when pressure is adequate. If shorting the switch engaged the clutch doesn't that mean the switch isn't closed when you want it to be? Which tells me you're low on gas.

What am I missing?

I think I'm missing it too

[RoxbyRat]

I know Im replying to A year-old post but Im having the exact same issues in my Feroza. A/C switch in Cab works, Gas Pressure Switches are closed (continuity across switches is achieved) and have proven the clutch functions smoothly when shorted from (+)battery.
Have been tracing wires with no great success.


...help?