• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

AC compressor cycling on/of 20 sec

Djurre-Avalanche

Djurre-Avalanche

Full Member
Joined
Aug 6, 2009
Messages
272
Location
Amersfoort, The Netherlands
When normal temperature is selected (for example 20 degree celcius or 68 fahrenheit) my AC compressor cycles on and off every 20 sec (after 20 sec it goes on, after 20 sec it goes off and so on) when i turn down the temperature, like 15 degree celcius, or 59 fahrenheit, the AC blows icecold air and the compressor stays on all the time.

When i select 20c or 68f again, it starts cycling again, is this normal?

AC serviced and refilled one week ago, they mounted a new condenser also.

2003 Avalanche with dual climate controls.
 
Sounds normal to me.
 
I bet it is low on refridgerant... cycle times tend to be minutes to ensure it runs long enough to remove moisture...
 
Like i said, it had a recharge one week ago, and they tested it for leakage.
The climate control system works perfectly, but i am unsure about the compressor coming on and of that fast.
When i select a temperature setting that's very low, the AC turns on, blows icecold, and the compressor stops cycling at that point, but is on steady.
If my system is low on freon, it should not stop cycling at that point i guess?

I did a search in google and allot of people have this, so maybe it's normal?

I don't know  ???
 
mine was not cold enough and i noticed the cycling times were short ,every 15 or 20 sec. so i added a can of r12 freon and measured with a gage its right at
2 1/2 pounds  blows ice cold now (y) and it doesen't recycle every 20 seconds . Its like sitting in a fridge ,not bad for a 2002  with 280,000 km on it
 
have them check high and low pressures again... to ensure it is properly full...
Slight loss on refridgerant is enough for it not to run long...

See as it starts to compress fluid the low side pressure reads too low so it shuts off compressor...

Either that or you have some control wrong......

Compressor should run like your House AC...
set controls where you want them and the cycle time should be minutes.

Put thermometer in center vent.
Set AC on HIGH recirc AIR.
rev engine and hold around 1000 to 1500 RPM

Wait several mins and thermometer should read 50F or so
If in 60F or 70F you have issues..
 
On my 03 back around 05 or 06, the AC System began to exhibit this problem.

I took it in for service and it required a charge. No leaks or other issues. The first symptom was the frequent and short cycling time and eventually, no cooling.

After the Recharge, it continued to do the short cycling time with minimal cooling for about 2 or 3 weeks, it just didn't seem to cycle long enough to really notice any appreciable cooling in the cabin.

I took it back, they rechecked it and said it was up to specs. After a few more weeks, it began to work as expected and finally reached to the point where I had to increase the temp settings upwards to keep from putting on a sweater during 90?f summer afternoons.

I never had a problem with it again and traded it in late last March.

Charge it up and give some time.

YMMV  :B:
 
Mine does cycle when it's not much temperature difference like 85 outside and set for 72, but when it's 90 outside and I set 68 then it comes on full time till the cabin is cool then starts to cycle to maintain the temp.
 
Mine cycles also when the outside temperature isn't very much different from the inside temperature, when i turn the AC to it's coolest it blows icecold air and the cycling stops..... so when the AC is needed, the cycling stops and the system blows cold air steady for as long as the AC is needed to cool down the car!

You could say it starts cycling when the AC isn't engaged.
So is the cycling at that point normal or not?

They put 750 grams of freon in it the last time.
 
resurrecting this thread. Having the same problem with my 03 Z-66

replaced the pressure switch. Still cycling 3 seconds on 5 seconds off.

any suggestions?

also still chasing after the airbag issue. Haven’t found any wiring issues under the seats, kick panels or door sill

Since I’m on it. Front amp sometimes only works when the drivers door is open. WTH

getting the truck ready to pass it to my son and want ac and airbags
 
what does ac pressure gages say when connected?
ON and off readings.

ya might just be low which means leak.
 
ErVikingo said:
Thanks for taking the time!

15 when on 80 when off
Click to expand...
Yeah, it's low of refrigerant. The compressor will cut off if the pressure drops below 20 psi or so while it's running. Depending on the leak, you might be able to get away with topping it off for now and seeing how it goes. But the permeant fix would be to put AC dye in it and find where it's leaking out.

Do not, under any circumstances, put refrigerant into the system that uses stop leak. This includes those $40 cans at the auto parts store with the gauge attatched. Only use a manifold gauge set and the cheaper, plain refrigerant. Or plain refrigerant with dye in it. You will clog the orifice tube up with stop leak.

Edit: as for the air bag issue, that depends on what it is. If you're just having a light pop up without any context, then you can get a code from that.

However, it is most likely to be the front impact sensors that have gone bad and are faulting out. Or the clock spring in the steering wheel losing some of it's connection to the air bag. (most obvious if another feature on the steering wheel, if you have one with buttons, also stops working)

The crash sensors are pretty easy to get to and replace. However, they're not cheap parts. (~$170 each give or take) A half decent scan tool like a bluedriver can gather that code as long as it hasn't been erased. However, it might jsut be easier and cheaper for you to have a dealer take a look at it and make a peroper diagnosis.

There's a specific error code for each side.
attached is a troubleshooting pdf on the crash sensor codes. And below, a video on how to replace one of the front ones as an example.

 

Attachments

  • 7e743b05-4b35-4008-ba11-95655c191c41_DTC+B0100,+B0101,+B0102,+B0103,+B0104,+or+B0105.pdf
    104 KB · Views: 2
Last edited:
Raekal said:
Yeah, it's low of refrigerant. The compressor will cut off if the pressure drops below 20 psi or so while it's running. Depending on the leak, you might be able to get away with topping it off for now and seeing how it goes. But the permeant fix would be to put AC dye in it and find where it's leaking out.

Do not, under any circumstances, put refrigerant into the system that uses stop leak. This includes those $40 cans at the auto parts store with the gauge attatched. Only use a manifold gauge set and the cheaper, plain refrigerant. Or plain refrigerant with dye in it. You will clog the orifice tube up with stop leak.
Click to expand...
I'm new here but I just want to second this. The stop leak AC stuff totally trashed the AC system in my jeep that probably could have just been topped off every so often. I miss AC on the trail...

Stay far far away from that stuff.
 
Thanks for the complete answers! I did get a kit from the store but doesn't have the stop leak. I'm afraid of those as they will clog internals (its what they do!).

I'll put in more gas and see how it goes. I already changed one of the crash sensors and the clock spring. That solved the issue for a year or so. I'll scan it and post codes.

Thanks SO much !
 
ErVikingo said:
ARGH, I used the wrong can. It does have some stop leak on it (yikes).

Airbag code: B0041 Left Side Deployment Loop Open
Click to expand...
Well, it's in there now. On the bright side, an oriface tube is about $7 from the parts store or $15 from the dealer. Just have to separate the AC line between the port fittings and slide it out. Simple if it becomes an issue. Though obviously the AC would stop working again if it did.

As for the air bag code.. i think you were on the right track. For the first gens, i think that's pointing to the driver's side seat connectors and related harness. I see a lot of people posting about broken wires. But i'd check the connector itself, make sure all of the wires are snug in the connector. There's a ton of videos that pop up with people jumping the pins to solve the issue. But i'm at work and cant really get the context going on there. Don't know if that's a bandaid fix to get the light to go away or if it actually repairs the problem.
 
I'm getting a can of "just gas" to complete filling up. I put approx 1/2 can of the one with dye and sealer (I misread and thought it only had dye).

I have read a lot about the pins. Seems to be a know/recurring issue with either a yellow or a black wire on the plugs under the seat. I have checked and not see anything close to the plugs (and have used contact cleaner) but I wonder if there is a frayed wire under the carpet, door sill or kick panel.

Thanks again!
 
ErVikingo said:
I'm getting a can of "just gas" to complete filling up. I put approx 1/2 can of the one with dye and sealer (I misread and thought it only had dye).

I have read a lot about the pins. Seems to be a know/recurring issue with either a yellow or a black wire on the plugs under the seat. I have checked and not see anything close to the plugs (and have used contact cleaner) but I wonder if there is a frayed wire under the carpet, door sill or kick panel.

Thanks again!
Click to expand...
It wont be surprising if you need 1-2 cans in total. I put 2.5 in mine when it was cycling in 5-10 second intervals. It doesn't seem like it needs to be a lot higher, but that's because the compressor cant take up any more when nothing is there, so it will drink quite a bit before you see the needle really move up during the compressor cycles.

You can do it in the store parking lot if you dont want to wind up with an extra can/ take another trip.
 
Last edited:
I've use the AC sealer in the past (on my old truck) and did not have any issues but the directions said to follow up the sealer with a can of plain refrigerant to clear areas like the service valve, etc which I did. Worked great for 3 years.

Two years ago when I "got" my AV, I had a slow AC leak that did not show up with the dye or any sniffer. So, I thought maybe it's the low or high pressure service valves. I purchased two Dorman AC service valve caps (the are brass and screw in real nice but expensive $7 each). Recharged the AC and screwed on the brass caps. It has be full and working great for two years now (I guess the caps are not so expensive ;-) Highly recommend trying that fix if you can't find a leak.

Not sure of the current prices but here is the item: https://www.dormanproducts.com/p-80262-902-025.aspx

Another related item, the Air Bag light. On my AV I had the light coming on. I did some research found something different than the usual sensor needing replacement which I figured I would try since I tested the front sensor and it was good:

If you have a ground wire on the truck that is broken, that can cause the air bag light and code to come on. As you may know or will find, the AV has LOTS of grounds (if I remember something like 7?).

Any how, I started in the engine bay and found that the connection for the ground from the HOOD to FIREWALL was broken. I fixed the connection and low and behold the Air Bag light went off and (thankfully) has not come back on and it has been over a year now.

And that's the rest of the story...
 
Thanks for the info! I ended up using 1/2 can of the gas with sealant and followed up with 1.5 cans of "just gas" as suggested by Raekal. My (non professional gauge) now shows 45 psi when the compressor is on. Cycling has gone away and it blows cold!!!!!!!!!!! I will save the link to the valves as the original leak was out of one (high pressure side) which i have not replaced since it is stuck on the housing. I was afraid of putting more "torque" to get it out.

Funny you would mention ground straps. That is a usual problem with one of my old cars. Ground strap goes bad and the clutch cable breaks. Yes you read that right. Clutch cable starts working as the ground and it damages the cable.

The strap from firewall to hood was broken before and i "crimped" it again. I will revisit that one first and check and clean the rest of them.

News to follow.
 
changed the firewall/hood ground strap with a new OEM one. Also cleaned and inspected another strap next to it. Still have the error... The hunt continues
 
Good on straps, can't hurt to have a new one.

Here is the page from the official GM dealer service manual for Airbag code: B0041

If you want more manual details let me know, I can post each page you need.

DTC B0040, B0041, or B0045​

Circuit Description​

The inflatable restraint side impact module deployment loop consists of a side impact module, side impact module high control, and side impact module low control circuits. A shorting bar is used on the side impact module connector which will short together the side impact module high and side impact module low control circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.

Conditions for Running the DTC​

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC​

  • DTC B0040 will set when the SDM detects the LF side impact module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
  • DTC B0041 will set when one of the following conditions occurs:
    • The SDM detects the LF side impact module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.
    • The SDM detects the voltage at LF side impact module high control is less than 2.4 volts and LF side impact module deployment loop resistance is 6 ohms or greater for 500 milliseconds.
  • DTC B0045 will set when one of the following conditions occur:
    • The SDM detects the voltage at LF side impact module high control is greater than 6 volts for 500 milliseconds.
    • The SDM detects the voltage at LF side impact module high control is less than 2.4 volts and LF side impact module deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken When the DTC Sets​

The SDM commands the AIR BAG indicator ON via Class 2 serial data.

Conditions for Clearing the DTC​

  • The condition responsible for setting the DTC no longer exists.
  • You issue a scan tool CLEAR DTCs command.
  • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids​

The following can cause an intermittent condition:

  • A short between the LF side impact module high and LF side impact module low control circuits
  • An open or high resistance in the LF side impact module high or LF side impact module low control circuits
  • A malfunctioning shorting bar on the LF side impact module connector
Refer to Testing for Intermittent and Poor Connections in Wiring Systems.

Test Description​

The numbers below refer to the step numbers on the diagnostic table.

    • Inspects the LF side impact module in-line connector.
    • Tests for a malfunctioning LF side impact module.
    • If DTC B0040 is present, test for a short between the LF side impact module high and LF side impact low control circuits. If DTC B0041 is present, test for an open or high resistance in the LF side impact module high and LF side impact module low control circuits. If DTC B0045 is present, test for a short to ground or voltage in the LF side impact module high and LF side impact module low control circuits.
Step​
Action​
Yes​
No​
Schematic Reference: SIR Schematics
Connector End View Reference: SIR Connector End Views​
1​
Did you perform the Diagnostic System Check - SIR?​
Go to Step 2​
2​
  1. Turn OFF the ignition.
  2. Disconnect the LF side impact module in-line connector located under the seat. Refer to Inflatable Restraint Side Impact Module Replacement - Front .
  3. Inspect both halves of the connector for the following conditions:
    • Corrosion
    • Terminal damage
    • Poor connections/terminal tension
Do the connectors exhibit any signs of corrosion, terminal damage, or poor connections?​
Go to Step 3​
Go to Step 4​
3​
  1. If the LF side impact module harness connector exhibits any of the above conditions, replace the LF side impact module wiring harness. Refer to Inflatable Restraint Side Impact Module Replacement - Front .
  2. Replace the harness side of the LF side impact module in-line connector. Refer to Connector Repairs in Wiring Systems.
Did you complete the replacement?​
Go to Step 11​
--​
4​
  1. Install the J 38715-A SIR Load Tool to the harness side of the LF side impact module in-line connector located under the seat.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, request the SIR DTC display.
Does the scan tool indicate that either DTC B0040, B0041, or B0045 is current?​
Go to Step 6​
Go to Step 5​
5​
  1. Turn OFF the ignition.
  2. Disconnect the J 38715-A .
  3. Reconnect the LF side impact module in-line connector.
  4. Remove the LF side impact module connector located at the module. Refer to Inflatable Restraint Side Impact Module Replacement - Front .
  5. Use the J 38715-30A adapter to connect the J 38715-A to the LF side impact module connector.
  6. Turn ON the ignition, with the engine OFF.
  7. With a scan tool, request the SIR DTC display.
Does the scan tool indicate that either DTC B0040, B0041, or B0045 is current?​
Go to Step 10​
Go to Step 9​
6​
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM connector for corrosion or damage. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?​
Go to Step 11​
Go to Step 7​
7​
  1. If DTC B0040 is present, test the LF side impact module high and LF side impact module low control circuits for a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. If DTC B0041 is present, test the LF side impact module high and LF side impact module low control circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  3. If DTC B0045 is present, test the LF side impact module high and LF side impact module low control circuits for a short to ground or voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?​
Go to Step 11​
Go to Step 8​
8​
Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
Did you complete the replacement?​
Go to Step 11​
--​
9​
Replace the LF side impact module. Refer to Inflatable Restraint Side Impact Module Replacement - Front .
Did you complete the replacement?​
Go to Step 11​
--​
10​
Replace the LF side impact module wiring harness. Refer to Inflatable Restraint Side Impact Module Replacement - Front .
Did you complete the replacement?​
Go to Step 11​
--​
11​
  1. Reconnect all SIR system components.
  2. Verify that all components, connectors and CPAs are properly mounted.
  3. Use the scan tool in order to clear the DTCs.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?​
Go to Step 2​
System OK​
 
You must log in or register to reply here.
Back
Top