dustyshiv

Hey Guys,

Have an LS400 1995 that has done 127k Miles. The AC was rock solid and took the desert heat of Dubai with no problems.

From last week however, the AC is mildly working upon turning on to Max cold with full blower speed. The AC light stays on solid though.

Here are some findings and steps that I have done already but with limited success.
1. Removed the Neg Term from the battery, put it back on after 5 min and checked for AC upon start up. Still same.
2. The compressor engages upon pressing the AC switch as is evident by the flow of Freon in the display window of the receiver and the RPM shoots up a bit.
3. Checked the level of Freon in the system through a top up machine and it was found to be 13 ounces. Topped it up to 18 ounces and checked. There is a bit more cooling but nothing as before. I have had this car for three years now and have never topped up. Never had issues with AC at all.
4. Checked all the fuses in the main fuse box under the hood and the fuse box near the left parking brake. All were good.
5. Did the AC diagnostics and got Code 21 and 24.
6. Drove the car as is for a week on a daily basis with full AC on to check if there is loss of Freon due to any leak. I can still see the Freon getting circulated through the display window.
7. Cleaned the Condenser through a pressure washer. No improvement. The cabin filter was cleaned recently as well.
8. The AC Fan comes on and runs smoothly.

I think the AC is trying to cool but unable to for some reason. I'm stumped.

Appreciate if you guys could help me out through your suggestions.

Thnx,
Shiv
Dubai

RA40

iTrader: (6)

Code 21 is the solar sensor, perform the test during the day. Code 24 is the magnetic AC clutch relay. If the R134A refrigerant is low, there is a leak that needs to be traced down.

Yamae

Code 24 is also the solar sensor, I believe.
There are two solar sensors. One at the driver side and the other at the passenger side.

Yamae

Other than those items you've checked, I'd check the A/C filter. A badly clogged filter limits the air flow.
I also would check the leakage using a UV leak tester.

Regarding the code 21 and 24, it is often the case to have those when checked not at under the sun.

LS400FAN

Yamae I'm also getting the code 21 and 24 (both pass. side solar sensor), could you tell me where the sensors are located? I can't seem to find the part number for this item as well, any ideas? Thanks much.

dicer

Also check that the condenser fans coming on. Did anyone use pressure gauges on the system? Readings?