Write-Up: AC Compressor & Clutch Replacement

albertj wrote:

Jack the R wrote:

My clutch is not engaging, but no there is plenty of coolant in the system and no codes are being thrown.  Any ideas?

Kindly tell me how you determined the amount of the coolant in the system?

Gauge on a can, bought from Wal-Mart.

albertj wrote:

And did you use a test light to see if your car is trying to switch the compressor clutch but the clutch isn't responding?

No.

Sorry JR, gauge on the Wal-Mart can most likely won't help you at all.

To check if the compressor and clutch is able to work, remove the 2 prong electrical connector that is on the accumulator (or also known as a Receiver/Dryer) near the firewall.
Then temporarily put a jumper wire or paper clip into each of the 2 female connections on the wiring harness while the engine is running and your watching the compressor clutch.

If the clutch engages and the compressor turns without any horrific noises you know the compressor and clutch assembly are good.

Only use the jumper for as short amount of time as it takes to see if the compressor runs, then pull your jumper wire.

If clutch and compressor turn OK then you need to hook up a proper set of A/C refrigerant gauges to check both the High and Low pressure side of the system to diagnose properly.

This yellow connector? The FSM says the cannister behind the headlight is the accumulator.

Sorry,
That's not correct. It may be that it leads to the accumulator, but I don't know. Just go to the accumulator to be sure. Unplug the low pressure 2 wire electrical connector from it and jump the wires in the harness you just disconnected. If your not sure what is what, take pic of the Accumulator - Receiver/dryer and post a pic of that for verification. I don't have a Riv to take a pic of and post it for you. But I know you'll find the connector that needs to be disconnected and jumped.

The Accumulator is a long vertical aluminum cylinder that the A/C hoses connect to and is close to the firewall.

Make sure you have your HVAC set for A/C on full cold, then.................................

There is an electrical connector on the accumulator that has only 2 wires going to it. Disconnect the electrical connector and jump the the 2 connectors that are in the wire harness that you just disconnected.

Then you should see and hear the compressor clutch and compressor come on and rotate. As I said in the earlier post, if you hear very loud noises coming from the compressor then you now know your compressor has fragged and you have a bit more work to do and more parts to replace.

Who am I to get into the conversation of two gurus? But still...
Rick, there are no any electrical connectors or wires on the dryer/accumulator. It really is just an aluminum canister with two hoses.


And indeed, it is located kinda in the fender, behind the headlight. Actually, part of its clamp can be seen on the Jack's picture.

Now Jack. Don't touch that yellow connector, it is connector for the front impact sensor/sensors of the SRS.
I'm pretty sure there are other ways to check the electrical part of the clutch. Just let me try something on my Riv...
BRB (probably...) )

Thanks deepfrozen.
I was off base on the Riv Accumulator. It's been a while and the whole time I owned mine I didn't need to do anything with the AC system. So, I shouldn't have commented on it without looking in the manual first.
Thanks for setting me straight and avoiding JR having to look for something that wasn't even there.

Well.
I'm sorry and hope I didn't mislead you JR. I was going from memory, but that's confused by several cars or engines in my memory.

There is an AC low pressure switch somewhere in the system that you can bypass to see what's happening. But you did say you tried to put freon into the low pressure port from Wal-Mart can of Freon with a gage. If it was low on freon, and you had it hooked up correctly, it would have taken the freon if it needed it. But not knowing what and where you hooked up to makes it impossible to daig over the net.

But the BEST way to do all this is get yourself a proper AC manifold with gauges tester. (Harbor Freight is OK for the occasional use you wil be using it for. Just need to be sure your getting one for R134A system.

You'll need to find out what you should be seeing for Low pressure and High pressure readings to see what is at fault with your system.

Or you could always bring it to a shop that you trust to just hook it up and give you an estimate based on what they see. And since you appear to not know what to look for as far as pressure readings and what they mean, a shop might be a better option for you on this.

I'm not trying to belittle you or question your intelligence or ability to learn, but it could be a more expensive learning curve than bringing it to someone you trust.

Now, if you don't have that trustworthy shop with people you like, then by all means buy the gauge set-up and we'll walk you through it.

Rick

The low pressure switch is pictured in the 1998 FSM, page 1-24.

I've looked through the A/C section of the 97 FSM, which is section 1B in the 97 FSM. I see nothing about a low pressure switch. There is a trouble shooting flow chart on 1B-11, which says to connect a "fused jumper wire" between the positive battery terminal and clutch coil terminal A to test for clutch engagement. If the clutch doesn't engage, then connect the jumper wire between a good ground and clutch coil terminal B.

There are some steps to go through before checking coolant pressure, so I'll get that much done.

Is a fused jumper wire a specific tool, or just a wire with a fused soldered into it? Wire gauge and fuse size are not specified.

Jack the R wrote:

I've looked through the A/C section of the 97 FSM, which is section 1B in the 97 FSM.  I see nothing about a low pressure switch.  There is a trouble shooting flow chart on 1B-11, which says to connect a "fused jumper wire" between the positive battery terminal and clutch coil terminal A to test for clutch engagement.  If the clutch doesn't engage, then connect the jumper wire between a good ground and clutch coil terminal B.

There are some steps to go through before checking coolant pressure, so I'll get that much done.  

Is a fused jumper wire a specific tool, or just a wire with a fused soldered into it?  Wire gauge and fuse size are not specified.

Fused jumper wire is just a wire with fuse socket crimped in.  They are short money at auto parts stores, usually you have to fix the ends yourself by installing probes, alligator clips or just strip about 1/2" of insulation at each end, twist, and tin the wire. After you have fixed the ends, put a fuse in the fuseholder appropriate to the circuit you are testing and go from there.

What size fuse would be appropriate for this job

Jack the R wrote:

What size fuse would be appropriate for this job

Can't remember if the AC system (compressor) fuse is located under the hood or in the panel by the drivers door.
Whichever, just look to see what the fuse rating is on there and match it if you feel you have to.
If you just use a jumper wire without soldering or twisting a fuse holder into a wire, it will be OK. Trust me.

As I said before, just jump the connection long enough to see if the compressor clutch turns and how loud the compressor is and then pull your jumper wire out.

This simple test will tell you if the clutch still works, if the compressor will turn with the clutch and if it it's quiet or noisy.

If the clutch turns and engages the compressor as it should, and the compressor doesn't sound like it's full of marbles then more than likely your AC system has leaked out enough freon to where the pressure is so low that the low pressure switch is stopping the clutch and compressor from engaging/

The Low Pressure switch is a safety device to save the compressor in case the system leaks enough freon to where it would be unsafe to run the compressor without it fragging on you.

"This is a test and only a test." Brought to you by the American Broadcasting System. Good Night.

Jack the R wrote:

What size fuse would be appropriate for this job

Check the fuse panel for an A/C or ACC fuse, however, since the circuit is just jumping the clutch I'd guess between 15 and 20 amps or so. Just go look. The point is that you need to protect yourself and the car's other circuits against a dead electrical (not electronic) short -- fuse will work out fine. It's just one of these

https://www.ebay.com/itm/14AWG-Wire-In-line-Car-Automotive-Mini-Blade-Fuse-Holder-Fuseholder-20A-I6E8/264219276736

and a reasonable fuse out of your box of spares. Strip and tin the ends of the wires and wha-la you have your fused jumper.

I've got the fused wire, should I use 10 or 15 amp fuse? Everything AC related in the dash panel is 10 amp, but I'm not sure any of it is for the compressor.

The terminals I've got to jump are, as you can see, not in the most convenient location. The FSM doesn't mention whether the engine needs to be running or not. Does it have to be? The remote charging terminal under the hood is surely hot all the time. AFAIK the car wouldn't have to be running for the first test, jumping between the +battery terminal and "Terminal coil A." If the clutch doesn't engage though, the next test is to jump between ground and "Terminal coil B." I don't see how that would do anything unless the accessories were on at a minimum, and the plug was plugged in.

I don't see anything in the FSM that says which Terminal coil is A or B. Anyone know?

Frankly, I'd try adding refrigerant to the system, that plug is going to be nuts for a hobbyist to get to given the whizzing belts.

So you're saying the motor has to be running?

The SC belt can at least come off, and the plug can come out with motor off. Unless it needs to be plugged in for the test. I don't know.

Jack the R wrote:

So you're saying the motor has to be running?

The SC belt can at least come off, and the plug can come out with motor off.  Unless it needs to be plugged in for the test.  I don't know.

Yes. That's why I'd try simply adding refrigerant. If everything else is working the system will come on after refrigerant pressure in the system passes a certain minimum (long before it's properly filled). Set the temperture to low (60 deg), follow the directions on teh can to add refrigerant. The connector only fits one of the ports under hood (the smaller one).

I've dumped a whole can into it and run it with the temp set to 60. Before I put more in I'll have to buy a good set of guages and confirm what the pressure is.

What I'm really trying to do is rule out the possibility it's a problem with the climate control module.

What is the air vacuum pump in this kit for - link

Jack the R wrote:

What is the air vacuum pump in this kit for - link

That is to totally evacuate the system for a fresh charge.

Vacuum pumps are used to evacuate the system as Larry has said.
But the function is more than that. The vacuum pump is used to pull a vacuum (as it's name would imply)
So, after it sucks all the remaining freon and more importantly any moisture out of the system, then you leave the pump hooked up for about 15 to 20 minutes, pulling out what it can. Note what the negative pressure is on the pump gauge or the Low Pressure gauge on your gauge manifold. These will read in Inches of Mercury. (inches of Hg)
Turn the pump off. DO NOT disconnect it.
Leave it for about a half an hour and check the gauge to see if it is still at the vacuum reading (" of Hg) when you shut it off. This will confirm that the system is tight and there are no leaks. If it only drops a small amount then you have a slow leak. A small loss of vacuum will determine whether you want to just re-fill the system periodically with freon.
Very small leaks are almost impossible to find without buying more testing equipment.
So, I would just keep my small thermometer in the dash vent with the A/C on high and check the air temp during the A/C season. The thermometer may be part of a kit you've purchased or you can get one at any auto parts store. I have both a Snap-On gage and an aftermarket gauge. I can read the aftermarket gauge much easier as it is larger than the Snap-On one. My eyesight has been getting worse over the years.
If that is the case and you feel that it's getting warmer or less cold in the cabin during the heat of the summer then use the small vent thermometer to keep tabs on what the system is doing and how warm the air is actually getting.
If the vent temp climbs to 50* plus during the heat of summer, while driving at speed (air moving over the condensor) then you can decide to add some freon to bring it back down to 40* to 45*.
If you decide to add some freon then should also be watching your gauges and keep a strong fan blowing at the condensor/radiator while your doing all this when it is Hot out. You need to simulate driving down the road to some degree. So your electric fans may be on and your adding air with an outside fan to help the system.
The exact pressure readings (Low and High) that you should see on the gauge set up will vary.
You need to read the manual and adjust for ambient temps.
To bring your inside vent temp down to 40* 50* max you will have to add some freon. May only need a partial can.
Regarding buying freon, do not buy the cans that have any stop leak in them that stuff can and does plug up the orife valve as the opening there is small. It's like putting radiator sealant in and causing more problems than fixing it the correct way. Also don't buy any of the expensive ones with hoses and a gauge on it if you've bought all the right equipment.
Look toward the Bottom shelf at the Auto Parts store and you'll find the can of R134A that has the lowest price. Don't be fooled by the cans that say they will cool your system better than the regular stuff for $10.00 more per can. It's all bullshit marketing. Buy the least expensive R134A from the bottom shelf or when it's on sale.

If you don't want to invest in the equipment necessary to do the job the correct way then bring it to your favorite mechanic. Everyone has one of those don't they.????

For better or worse, I am my favorite mechanic

My AC clutch is not engaging, so I'm getting no cool air at the vents at all.

Jack the R wrote:

For better or worse, I am my favorite mechanic

My AC clutch is not engaging, so I'm getting no cool air at the vents at all.

So am I, but if I didn't have the tools in some instances I would bring it to a shop I trusted.
That was when my back was flexible and my brain worked. I'd still pay the people that had the experience and all the special tools to do things like Trans overhauls and other things that I didn't have much experience with nor the proper special equipment to do the job.

I just clicked on the link you provided from the auto parts store and that seems to be a complete kit for doing R134a systems.

Don't know what the prices would be if you compared it to Harbor Freight. But if you don't have a HF store near you to return the stuff if it's bad out of the box, or if you want to return it after you've fixed your A/C system (OH, none of us have done that before) Then the price from the Auto Parts store isn't bad and you'll get what you need to at least diagnose the problem and if you have a leak as I mentioned above then you can look into the leak detection equipment.

Remember you could still have a bad compressor clutch. But other than doing what Albert has already suggested about using a fused jumper wire across the compressor wires or find the low pressure switch harness and jump it there, you won't know.

But, as you know, where always here to walk you through it even if we have differing opinions on what to look for and how to perform some tests.
Hopefully there are still some active ASE certified mechanics on the forum to help you through the difficult times. But you certainly want to get the A/C system fixed while it's cool outside and not when you have to bend over the hood with the engine running when it's 100*F out and 90% humidity.

I'm following the flow chart in the FSM. The next step was to jump between the positive battery terminal and "Terminal coil A" The FSM doesn't say HOW to jump it though, or which terminal is "A." The rearmost terminal has a green wire going to it, which I assume is positive. With the design of the plug, I don't see how it would be possible to jump the terminals with the plug in place.

Jack the R wrote:

I'm following the flow chart in the FSM.  The next step was to jump between the positive battery terminal and "Terminal coil A"  The FSM doesn't say HOW to jump it though, or which terminal is "A."  The rearmost terminal has a green wire going to it, which I assume is positive.  With the design of the plug, I don't see how it would be possible to jump the terminals with the plug in place.  

It's called Back Probing. You need a fine tipped tool to enter the back side of the connector where the wires actually fit in.
Don't want to pierce the insulation on the wires so they call for back probing.
Back in the day, we would always just puncture through the insulation to test a circuit but I wouldn't recommend it.

Also, another tool that has become very valuable in troubleshooting wiring and electrical problems is the Power Probe.
This tool allows you to put the tip of the probe into the back of a connector and apply 12 volts if thats what you need to do.
It does many other things also.

But due to what it cost's you are better off using the digital ohm meter and jumping connectors as needed.

I sure wish you lived closer because I'd be more than happy to bring all my electrical troubleshooting tools, home made jumpers and all the Air Conditioning tools you need to get er done.

Nuh-uh, I'm sure you wished you lived closer so your Riv wouldn't have been rusted out by road salt