My 98 C280 AC is blowing hot air from all vents. Here are my codes with the engine running and ambient air at about 96F.

01 - 96F
02 - 95F
03 - 101
05 - 101
06 - 140
07 - LO
08 - 93F
09 - 50F
10 - 465
20 - 000
21 - 070
22 - 000
23 - 000
24 - 13.7
40 - 02
41 - 03
42 - 18
43 - 6-C
50 - 100
51 - 72F
52 - 50F
54 - OFF

Thoughts?

Thanks in advance for your time and patience.

Of course #7 is the problem, should be between 3-30.
That is the reading from the pressure switch on the drier.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

By looking at the other readings, can I wager a guess that it MIGHT be a defective pressure switch?

Or the system is empty.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

With the gauges attached and engine idling, I am reading about 186 lbs on high side and about 36 lbs on low side.

Switch?

It appears that the pressure switch has 3 contacts (see pic below). Can someone tell me what I should measure across the switch contacts with a dvm and what the wires connect to? I know some guys on here have said they shorted the contact wires to test and make sure it was a defective switch. Across which of the 3 wires?

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