Passenger Side AC/Lack of

terryjm1

Well-known member
Jan 23, 2011
1,486
375
I got back around to dealing with this today. This is on my 98 that I purchased with a bad engine. So, I never had the ac running before I switched to the 300tdi. When I pulled the old 4.0, I sold the entire engine harness and removed the ECU thinking I wouldn’t need it. For the most part, that was a correct assumption. However, I couldn’t begin to figure out the wiring for the AC. (Multiple relays and sensors all talk to one another in the process of delivering cold air.) So, I completely rewired it including installing a new relay and bypassing almost all of the LR wiring and it now functions with a single relay, compressor cut out switch, pressure hi/low switch/sensor, and the anti-icing switch/sensor.

Seems I did an ok job as after adding 12 ounces of refrigerant today my passenger side warm air issue resolved. Also, it gets down to about 38 degrees at the vent on both sides before the compressor cycles off. It cycles back on at about 48 degrees and the cycle repeats.

Is it normal to cycle in this manner? I’m assuming this is the anti icing switch/sensor at the evaporator doing it’s job.

Another note on this, I was getting 42 degrees out of the drivers vent before I added the 12 ounces of refrigerant and just under 60 on the passenger side. With adding the 12 ounces it is 38 to 40 on both sides consistently until the compressor cycles off and both sides rise to just about 48-50 until the compressor cycles back on. There may be a 1-2 difference warmer on the passenger side but it is hard to see on the little dial gauge to say for certain.

Finally, I am relatively inexperienced on charging AC systems. I learned when you add refrigerant you have to give the system time to fully circulate the added refrigerant before the gauge readings can be considered valid.
 
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terryjm1

Well-known member
Jan 23, 2011
1,486
375
Following up upon my previous post. I took the D1 out of the cool mountain high elevation environment into the 90 degree desert yesterday and got 42 to 44 degrees from both sides and even the back seat occupant was comfortable. (Non rear air model.) The experiences discussed above were at 75 degrees outside air temps. I knew this was not the best test environment but it is a 45 minute drive to get to warmer temperatures where the AC is desirable. This is my first LR where I put much of any effort into the AC. I had heard how terrible the AC works. I must say, it seems quite adequate. For the TDI conversion it got a new compressor with clutch, new hoses, new drier, and new o-rings at every joint.

However, the 300tdi has just enough power to climb back up the mountain without the AC on. As soon as the incline gets more than subtle, the AC gets turned off. But, the outside air temps decrease along the way making the windows all that is needed.
 
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