My 98 ML320 has intermittent ac also. The #44 fuse is fine and the refrigerant is OK too. At static, it reads 100psi and with the compressor running about 30 on the low side and 325 on the high side. All in the normal range for a 90 deg temp.

The compressor may not engage for several days then oddly starts working again. When the compressor kicks in the aux fans work great and it blows 38 deg air in 90 deg temps.

I'm baffled by this. I tread a visit to the MB dealer but it's beginning to look like I can't avoid it. I've taken it to an indie ac tech and all checks out fine. He recommended the dealer next. Says the AAM is not directing the compressor to turn on.

Does the AAM control the compressor in the 98 ML? Anyone have any ideas other than taking it to the dealer? TIA.

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99 E300 133K
98 ML320 99K
87 Saab 900 Turbo Conv 123K