93 300E 2.8 US car auto climate controls, the a/c cools but barely, fan works but also barely (probably is low speed only). Just finally bought an a/c manifold set and checked it this morning, the low side pressures were crazy high, eventually hitting the top of the gauge. The high side was just a bit low. Driving it an hour or so later the air from the vent is at 52 while it is 88 outside.

I am new to working A/C’s. Any idea‘s?


Lol, just looked at my profile and my last log in was 2015!!!

I would evacuate, vacuum and charge per weight to start and then see what the numbers look like.

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Jim

X2 on evacuate and recharge with the exact weight required and I'll add to it, consider replacing the drier at the same time. A drier is cheap and is good maintenance on a system that old.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

That sounds like the plan then. I guess I was confused a bit that it was actually cooling somewhat with the pressures so out of wack.

On the blower barely blowing is that more likely to be a regulator issue or contacts/solder issue? It definitely blows and there are some changes from low to auto to high but not very much ). It definitely doesn't sound like the dying motor in my 190e. Damn noisy ass thing!

Check the strip fuse very closely for hairline cracks on the LF shock tower under a small plastic cover first, then check all fuses in the fuse box.

If the fuses are all good my guess is it is most likely the blower motor regulator under the wiper and blower motor. Pull the wiper, blower, clean everything and oil, inspect the blower for worn brushes replace as necessary, remove and replace the regulator.

It could also be the PBU Push Button Unit in the dash. I think the PCU controls the blower speed by varying the voltage to the yellow??? wire at the three wire connection by the brake booster. Voltage should vary from about 0-7 volts from the PCU fan speed control positions.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer