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Bus air not cooling
Bus air not cooling 2007 H D60. Appears compressor clutch not engaging. Is there a fuse that could be out? Would low Freon also cause the clutch to not engage?
Any recommendations for repair in Salt Lake City or Boise?
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17 Replies
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Chris
You have what’s referred to as dash air or Prevost driver air. Bus air is OTR.
If your compressor was short cycling it is low on Freon. Some compressors will disengage the clutch if low on Freon to prevent lockup. Some also will give you a blinking light on the face plate of the dash panel.
You could probably find a truck repair or charter bus service around SLC. After Boise your dead until the westcoast I would think.
Later
bv
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Lewis Bros Tour in SLC
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is there a fuse I should check. Looked in both areas (under driver and in front of engine in passenger side) without seeing anything listed for A/C
Thanks I’ll call Lewis Bros. In the past I would get the “low pressure” light on the dash. When I had it ch3cked they said nothing wrong, ignore it. Guess that may be wrong. Not bad driving with the roof airs and a fan blowing up front.
as an aside, the shop listed as Prevost authorized on the Prevost app wanted nothing to do with anything Prevost.
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is there a fuse I should check. Looked in both areas (under driver and in front of engine in passenger side) without seeing anything listed for A/C
Thanks I’ll call Lewis Bros. In the past I would get the “low pressure” light on the dash. When I had it ch3cked they said nothing wrong, ignore it. Guess that may be wrong. Not bad driving with the roof airs and a fan blowing up front.
as an aside, the shop listed as Prevost authorized on the Prevost app wanted nothing to do with anything Prevost.
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Chris, Jeff can probably walk you through your problem. In the past I too had low pressure issues, turned out to be the low pressure switch, but could also be a Freon leak as well.
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Dr. Yetter,
Had low pressure light flash on my 2007 Marathon H when in normal service. It was suggested that replacement of switch would solve problem. I did that and worked just fine.
AL
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Thanks,
I’ll check with the final authority…Jeff. Was hoping it was just a simple fuse – hahaha – never simple
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This happened to us on the road in June. Compressor clutch didn’t engage. I changed a relay in the box above the engine and that worked. I did have to sort of get to the back of the panel and make sure the wires were well seated on the relay… they push out of the panel pretty easily.
There are “map legend” sheets stuck to the doors on the engine compartment.
I also like to keep some of the alligator clip jumpers on board to check things. That’s how I figured out the relay wasn’t working.
I also keep one of those R 134 cans with the gauge to check the Freon level. Not precise or anything but will tell you if it’s gone…
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Thanks I’ll try both.
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We had the same problem. Clutch would not engage. Good pressure, R134A all ok. Low and high pressure switches worked properly. After hours of trouble shooting we came to the conclusion it was a small sensor in the air intake on the driver side of the bus that gave us trouble.
Prevost OTR specialist was extremely helpful going through the complete systen. Learned a lot.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
What is “Prevost OTR specialist” ? Mike
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i got a hold of him at Prevost Quebec. Don’t remember his name but he works for Prevost and is the OTR specialist at Prevost.
My son worked for a large tour bus company and got me his number.
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when we work on R134 and R1234yf A/C systems where clutch isn’t engaged on vehicles and equipment, first thing we do is attach a/c gauges to check static pressures – very quick and easy. No minimum pressure, binary switch shutting down system, as designed. If there is minimum system pressure, we start hitting the simple things first. Do you have power on both sides of the binary switch or fuses blown? Checking the binary first is a good indicator of if the switch has failed or if you have power to that point. If switch checks out, tells us if the issue is upstream or downstream.
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Low Freon can cause that, also there is a small filter that is located on the manifold located on top of compressor that has a line that goes to a manifold where all the sensors are. That filter gets clogged up and does not allow the Freon to get the the manifold and the sensors/switches don’t pick up pressure so the fans won’t kick on nor the compressor.
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Ralf-
Is it possible for you to post a photo of that filter location?
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