A/C Freezing up,93 300E

[SRI inc]

93 300 E 2.8

On a long trip this weekend i noticed my ac started blowing a bit warm , i stopped to get gas and checked under the hood and noticed the cold side pipe on the a/c had ice on it (the larger hose) from the small divider near the strut tower back to the firewall

its a r134 system ,could i be low on a charge ? or could the evap drains be clogged? the a/c works great during the day when i make my short trips and never noticed a problem before this 3 hour trip

the a/c is virgin never been opened or any repairs on it , the sight glass is tough to see cause the abs partially blocks it

any ideas

thanks

[J.HIDALGO]

The evaporator has a temperature sensor on the driver's side by the accelerator pedal. Tech's may give a clue how to test it! Also, do you see water coming out from the bottom of the car, as in the drainage tubing working properly. Also, the inside temperature sensor may be acting up or the pump that "sucks" air through a small screen on your overhead lights may not be working (sucking air). An easy way to check this pump if it is sucking air is, get an smoke producing "agent" and see if the smoke is sucked into that screen.
Good luck!

[mbdoc]

J.H. is correct the evaporator temp sensor is a likely failure! Testing won't help unless you can duplicate the same conditions as when the system froze up. Replace the sensor & then drive for a couple of hrs to see.

[SRI inc]

Sounds good thanks for the help , so i should not be worrying about being too low or to high on charge? also is the sensor near the kickdown switch ? or do i need to remove the center dash to get to it ?

thanks again

[Benzmac]

Don't worry about charge.

The sensor can be accessed through the underside of the drivers kick panel beside the accel pedal.

Can you tell me where the evaporator sensor is located on the 16 valve 190? I think mine might be on the fritz also. Thanks, Joe