Air con

[Mr_D]

The engine air con isn't working. With the engine running I turned on the air con to high, the fan to high and the temp to low then checked the compressor clutch. It isn't engaging so I guess I'll start checking fuses and wires.

[bullheaded]

Or no freon?

[Mr_D]

Originally Posted by bullheaded

Or no freon?

Maybe true as I guess the clutch won't engage if there is no pressure although I'm not sure about that.

[BBM3]

Mr_D,
A couple of things you can check.
You will need a multimeter and a piece of insulated 14 gauge wire with 1/2 inch of insulation removed from both ends.

DO NOT ATTEMPT EITHER OF THESE TESTS WITH THE ENGINE RUNNING!
REMOVE THE IGNITION KEY AND PUT IT IN YOUR POCKET!
SWITCH THE MAIN BATTERY SWITCH IN THE ENGINE COMPARTMENT OFF!

First check the pressure sensor:
You will see two refrigerant lines connected to the top of the compressor.
One of those lines will have a pressure sensor with a two wire harness and connector.
Unplug the connector and test the switch continuity with your multimeter.
You should see something very close to 0 (zero) ohms.
If so the switch is closed, normal.

Second (if test one passes) energize the clutch:
You will find a single wire and connector on top of the compressor headed to the clutch.
Unplug the connector and push one end of your wire into the clutch side of the connector and briefly (one second) touch the other end of the wire to 12 volts. The main shutoff power switch should be a handy 12 volt source.
You should hear the clutch click, engage.

These are the first things I would check.

Regards,
Bill and Nancy

[Mr_D]

Originally Posted by BBM3

Mr_D,
A couple of things you can check.
You will need a multimeter and a piece of insulated 14 gauge wire with 1/2 inch of insulation removed from both ends.

DO NOT ATTEMPT EITHER OF THESE TESTS WITH THE ENGINE RUNNING!
REMOVE THE IGNITION KEY AND PUT IT IN YOUR POCKET!
SWITCH THE MAIN BATTERY SWITCH IN THE ENGINE COMPARTMENT OFF!

First check the pressure sensor:
You will see two refrigerant lines connected to the top of the compressor.
One of those lines will have a pressure sensor with a two wire harness and connector.
Unplug the connector and test the switch continuity with your multimeter.
You should see something very close to 0 (zero) ohms.
If so the switch is closed, normal.

Second (if test one passes) energize the clutch:
You will find a single wire and connector on top of the compressor headed to the clutch.
Unplug the connector and push one end of your wire into the clutch side of the connector and briefly (one second) touch the other end of the wire to 12 volts. The main shutoff power switch should be a handy 12 volt source.
You should hear the clutch click, engage.

These are the first things I would check.

Regards,
Bill and Nancy

Thanks, I'll give that a go!

[BBM3]

You are most welcome.
Let me know if you would like pics or more details.
-BB

[Mr_D]

Originally Posted by BBM3

You are most welcome.
Let me know if you would like pics or more details.
-BB

On our compressor there is no pressure sensor on the lines in or out, no wiring for one either. Spartan says they installed the compressor and to call if I need more info so I'll do that Monday I guess.

[BBM3]

Here is a picture of my '05 DSDP w/ 375 ISL.
I would have thought yours would be very similar if not the same.



Regards,
-BB

[Mr_D]

Originally Posted by BBM3

Here is a picture of my '05 DSDP w/ 375 ISL.
I would have thought yours would be very similar if not the same.



Regards,
-BB

Mine looks the same (other than dirtier!!) minus the pressure sensor and wiring

[Mr_D]

Cummins says: bad fuse (nope, it's good), short in wiring or low "freon" I suspect low "freon" and I have to call Newmar for more info on what to use and how much. After 9 years and never been serviced I suspect it's just leaked out.

[Mr_D]

I emailed Newmar, they gave me the type of "freon" I need and the amount. Luckily they also gave a link to the Evans Tempcon site as I found I had a different condenser unit and it took more.
I found the pressure switch under the front "hood" and measured the Ohms and got 0.

So far the fuse checks OK
The pressure switch checks OK
Since I know the compressor isn't starting from visually checking it I'll have to dig deeper I guess.
Evans Tempcon will not give any info out to owners.

[wa8yxm]

Follow the wires from the compressor back toward the dash.. You should see 12 volts all the way with the unit turned on.. My guess is the dash switch itself.

There most likely is no thermostat in the line, they control temp by mixing hot air in insted of stopping the compressor.

[BBM3]

Originally Posted by Mr_D

I found the pressure switch under the front "hood" and measured the Ohms and got 0.

So far the fuse checks OK
The pressure switch checks OK
Since I know the compressor isn't starting from visually checking it I'll have to dig deeper I guess.
Evans Tempcon will not give any info out to owners.

Hello M_D,
Good work finding the pressure switch!
Just to be clear on measuring the continuity of the pressure switch and the difference between zero ohms and infinity ohms.
Sorry if you already know this...

On the bench.
If you are using an analog meter set to the resistance (ohm) scale when you touch the two leads together the needle should swing full scale from left, infinity to right, zero.

Digital meters will read something like OL with the leads open and 0 "zero" with the leads touching each other.

If when you disconnect the pressure switch harness and put each lead of your meter across the pressure switch you will see something close to zero ohms if your system is charged with freon and the switch is working.

You probably know all this however I'll make and post a quick video of the process if you would like.

Regards,
Bill and Nancy

[Mr_D]

Originally Posted by BBM3

Hello M_D,
Good work finding the pressure switch!
Just to be clear on measuring the continuity of the pressure switch and the difference between zero ohms and infinity ohms.
Sorry if you already know this...

On the bench.
If you are using an analog meter set to the resistance (ohm) scale when you touch the two leads together the needle should swing full scale from left, infinity to right, zero.

Digital meters will read something like OL with the leads open and 0 "zero" with the leads touching each other.

If when you disconnect the pressure switch harness and put each lead of your meter across the pressure switch you will see something close to zero ohms if your system is charged with freon and the switch is working.

You probably know all this however I'll make and post a quick video of the process if you would like.

Regards,
Bill and Nancy

Analog meter, needle goes full right when touching contacts on switch, same as touching the leads together. I assume this means the switch is closed. So this means the switch is normally open then and I'm low on "freon"?
Guess it'd be easy to check by just disconnection the leads to the switch and see if the clutch engages?