Red dot ac install

Dpas1973 · Oct 13, 2020

Maybe someone has a diagram on the hose hook up on a red dot ac system with a rear mounted condenser set up. The previous owner said he tried to hook it up but it never worked. I took it to get charged today and the compressor just clicks and the fault light says check compressor clutch. I’m not sure if he hook the high and low hoses up the right way on the condenser and evaporator from the compressor. Anyone help me out here?

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Coug · Oct 13, 2020

Here is a link to the Red Dot service manual. It's for civilian systems, but it's still just a basic aircon system, so it works.

https://www.btrac.com/documents/rd-service-manual.pdf

The only real difference in the civilian systems and military systems looking at the images is that the military system uses -12 hose size for the return from evaporator to the compressor, where the diagrams all show -10.

Small line from compressor runs to condenser. (line size is -8 )
Then from condenser to receiver/dryer. The receiver dryer IS directional, it won't function properly if installed backwards. (line size -6)
From receiver/dryer it goes to the evaporator (line size -6)
Then from the evaporator back to the compressor (line size -12, fitting size -10)

There an expansion and metering valve in there as well, but it's part of the hard tubing in the evaporator assembly so no need to worry about it.

This image is at the front of the Red Dot parts catalog. Very few military system parts in it, just part numbers for some of the fittings if you ever need to replace them

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Dpas1973 · Oct 14, 2020

Coug said:
Here is a link to the Red Dot service manual. It's for civilian systems, but it's still just a basic aircon system, so it works.

https://www.btrac.com/documents/rd-service-manual.pdf

The only real difference in the civilian systems and military systems looking at the images is that the military system uses -12 hose size for the return from evaporator to the compressor, where the diagrams all show -10.

Small line from compressor runs to condenser. (line size is -8 )
Then from condenser to receiver/dryer. The receiver dryer IS directional, it won't function properly if installed backwards. (line size -6)
From receiver/dryer it goes to the evaporator (line size -6)
Then from the evaporator back to the compressor (line size -12, fitting size -10)

There an expansion and metering valve in there as well, but it's part of the hard tubing in the evaporator assembly so no need to worry about it.

View attachment 815021
This image is at the front of the Red Dot parts catalog. Very few military system parts in it, just part numbers for some of the fittings if you ever need to replace them

WD 2019_Flip

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user-qqe34dh.cld.bz

The compressor just clicks and I have 3 blinks saying check ac clutch I’m assuming a bad compressor?

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Coug · Oct 14, 2020

Dpas1973 said:
The compressor just clicks and I have 3 blinks saying check ac clutch I’m assuming a bad compressor?

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unless you have an issue with your wiring somewhere, then it's likely the compressor.

I believe the red dot systems use a Sanden compressor, which takes SP-15 oil, rather than PAG-15 (not sure what the difference is, but Sanden likes their own oil better)

Dpas1973 · Oct 14, 2020

Coug said:
unless you have an issue with your wiring somewhere, then it's likely the compressor.

I believe the red dot systems use a Sanden compressor, which takes SP-15 oil, rather than PAG-15 (not sure what the difference is, but Sanden likes their own oil better)

So after 3 hours at the shop today they have no idea they are saying there is a blockage somewhere because the compressor keeps clicking every 10 seconds and not circulating the gas. They have no clue they were like maybe it’s the metering device but they said they doubt it’s the compressor because it’s trying to start. They jumped out the low pressure sw and nothing. Anyone have an issue like this?

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juanprado · Oct 14, 2020

Have they tried flushing the lines, evap, cond, etc? What does the gauges read on high and low sides?

Dpas1973 · Oct 14, 2020

juanprado said:
Have they tried flushing the lines, evap, cond, etc? What does the gauges read on high and low sides?

No idea I asked the guy at the shop if he can blow the lines out and his answer was we don’t have nitrogen here. There was no pressure because it would not cycle the guy at shop said he put 4lbs of 134a and all it does it click the compressor and flashed on the Controll module check ac clutch

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Retiredwarhorses · Oct 15, 2020

Dpas1973 said:
No idea I asked the guy at the shop if he can blow the lines out and his answer was we don’t have nitrogen here. There was no pressure because it would not cycle the guy at shop said he put 4lbs of 134a and all it does it click the compressor and flashed on the Controll module check ac clutch

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Sounds like a crap A/C shop, if They knew what they were doing they would know how to override
the pressure switches and test the compressor, I also wonder how he got 4lbs of r134 into the system
if the compressor was not running...literally impossible to do.

Dpas1973 · Oct 15, 2020

Retiredwarhorses said:
Sounds like a crap A/C shop, if They knew what they were doing they would know how to override
the pressure switches and test the compressor, I also wonder how he got 4lbs of r134 into the system
if the compressor was not running...literally impossible to do.

I agree. The clutch just clicks I’m wondering if the compressor is shot? Also how do you jump out the switches just a wire across them?

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Retiredwarhorses · Oct 16, 2020

Dpas1973 said:
I agree. The clutch just clicks I’m wondering if the compressor is shot? Also how do you jump out the switches just a wire across them?

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yes, just apply 24v direct to compressor.

Dpas1973 · Oct 20, 2020

Ok this is where I’m at I replaced the expansion valve did a nitrogen test no leaks and charged it up and the red light still blinks check ac clutch even when the clutch is engaged and the ac is working any ideas? Should I replace the compressor? Not looking to spend 275 after I already spend 540 on this ac system

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Dpas1973 · Oct 21, 2020

Retiredwarhorses said:
yes, just apply 24v direct to compressor.

Now it’s flashing check sensors when I had it working yesterday any ideas? Now the compressor won’t start

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Dpas1973 · Oct 21, 2020

Anyone lol

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Coug · Oct 21, 2020

My guess would be that either one of the switches or the wiring is having some type of issue.
It's not a complicated system, if it's working correctly then:

The manual I linked earlier has a troubleshooting section that, while it isn't specific for the HMMWV, it does cover the basics. Go to chapter 10 in the guide and read up about the AC clutch circuit.
The flashing lights on the evaporator are just a guide as to where to look, it doesn't tell you the specifics.

https://www.btrac.com/documents/rd-service-manual.pdf

Not to be harsh or anything, but we aren't there in front of the unit and can't point out what's wrong from just a blinking light, so you're going to have to read up and try to understand exactly how the system works in order to figure out what sensor/switches and wiring to check. You'll need a multimeter for all of this (voltage checks at switches and wires, and continuity tests through the same switches, as well as making sure nothing is shorting to ground)

But to say again, the blinky lights first said it was the clutch, and now are saying sensor. To me this means that it's very likely you have either a wiring issue (either a bad connection, shorted connection, or open) or a sensor/switch is not operating within specs.

Dpas1973 · Oct 22, 2020

Coug said:
My guess would be that either one of the switches or the wiring is having some type of issue.
It's not a complicated system, if it's working correctly then:

The manual I linked earlier has a troubleshooting section that, while it isn't specific for the HMMWV, it does cover the basics. Go to chapter 10 in the guide and read up about the AC clutch circuit.
The flashing lights on the evaporator are just a guide as to where to look, it doesn't tell you the specifics.

https://www.btrac.com/documents/rd-service-manual.pdf

Not to be harsh or anything, but we aren't there in front of the unit and can't point out what's wrong from just a blinking light, so you're going to have to read up and try to understand exactly how the system works in order to figure out what sensor/switches and wiring to check. You'll need a multimeter for all of this (voltage checks at switches and wires, and continuity tests through the same switches, as well as making sure nothing is shorting to ground)

But to say again, the blinky lights first said it was the clutch, and now are saying sensor. To me this means that it's very likely you have either a wiring issue (either a bad connection, shorted connection, or open) or a sensor/switch is not operating within specs.

Do you have any idea where I can get parts? The check sensors light started blinking after I unplugged and cleaned the 2 relays in the evaporator. I can’t find any place to get parts I put my model # in online and nothing comes up.

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Coug · Oct 22, 2020

Dpas1973 said:
Do you have any idea where I can get parts? The check sensors light started blinking after I unplugged and cleaned the 2 relays in the evaporator. I can’t find any place to get parts I put my model # in online and nothing comes up.

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no, I don't know.
You MIGHT be able to contact Red Dot and ask them.
There is always the chance that you can remove the relay and find a part number of some type printed on it.
Another option might be take it into a specialty electronics store and ask them if they can identify it.

Red Dot does have a parts catalog with pictures and part numbers. I don't recall looking at any of the relays in mine so I am not much help with identifying them

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juanprado · Oct 22, 2020

2nd posting the numbers off the relays as there are probably bosch style and out there in the aftermarket. Maybe also a picture of the connector also.

Dpas1973 · Oct 29, 2020

Anyone know how to bypass the low pressure switch? Putting the 2 wires together does not work?

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Coug · Oct 29, 2020

Dpas1973 said:
Anyone know how to bypass the low pressure switch? Putting the 2 wires together does not work?

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Have you used a multimeter to see if the switch is open or closed?
And have you checked to see if there is even voltage at the switch when the system is turned on?

I'd imagine the switch is probably normally open, and remains open at low pressure. It is closed as long as there is enough pressure in the system. It should be relatively simple to check with a multimeter set to continuity check.

If putting the two wires together doesn't work, then very likely something else is the reason. Check to make sure there is voltage on the wires (or rather at one of the wires, the other shouldn't have any) to ground.

Dpas1973 · Oct 29, 2020

Red dot stated my switch is a transducer that sends a signal to the protect module and they don’t sell the switch seperate from the charging port. And they don’t know a way to jump it out. It’s 1-4v depending on pressure

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Red dot ac install

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