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Red Mk1a Mr2
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Discussion Starter · #1 ·
To sum up all of below, basically idk why my ac compressor clutch is not receiving power after r134a retrofit install. I didn't test old or new compressor prior to install, and my AC didn't work in my aw11 since I purchased it back a few months ago with the old R12 compressor. I Also removed the high pressure sensor in the frunk to test it out but only destroyed it in the process, so I have to buy a new one prior to addressing the issue and can't find one with the connector already installed. Idk if the heater core in the dash has anything to do with the ac system / retrofit since it wasn't addressed in the YouTube vid I watched.

I didn't want to deal with the hassle of sourcing R12 and shops that still provide R12 AC services, so I went to YouTube and watched how to do a R134a conversion and bought all the parts in the video's description. Removed the old parts and once the new parts arrived, I installed the new retrofit fittings, Denso compressor with PAG-46 oil and new accumulator and reinstalled ac pressure lines with Santech r134a compliant o rings and gaskets, except on the biggest gasket on the compressor that was shaped like a rectangle. I skimped on that because my Santech gasket kit didn't come with one big enough to fit the compressor and the old one seemed in OK condition.

I went to get my old r12 recovered / flushed (if there was any) at some hole in the wall shop that charged me 30$ for a flush and fill with my own refrigerant. But I was in and out in a suspiciously short amount of time, roughly only 30 mins.
So idk if I actually got a flush or had a vacuum pulled on the ac system prior to them filling with the new refrigerant. They filled the system with 6 oz of R134a refrigerant and the high side pressure was at 52 psi. When I went to test if it worked with them they told me to turn ac on blast in the interior and nothing happened. The mechanic told me my ac compressor clutch wasn't engaging and showed me and then brought out a tester light to test the connector and had no luck.

Also pretty sure my battery or alternator is bad which idk if that could affect the compressor not receiving power. My headlights have been turning on but won't pop up and I took battery out and charged it from 20% to 60% and 3 days later took the battery out and it was down at 40% again. No bueno and no clue if that could be affecting all of this mess.



part number: 471-0136
 

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91t gen5
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Ester oil is what you are supposed to use with a r134a conversion, PAG isnt supposed to do well with the original mineral oil. You did say you had it flushed but that was with the whole system put together at the shop?

If the low side pressure isnt high enough the AC amplifier wont command the clutch to turn on, same goes with the high pressure switch.

6oz of any refrigerant isnt enough I would not go back to that shop just glad they only got $30 out of you. A quick search says the original R12 charge was 30oz so that means you should have charged 24oz of r134a.

You should spend the $200 or so and buy a vacuum pump and manifold gauge so you can do this yourself. Or you need to make friends with someone who knows what they're doing.
 

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Red Mk1a Mr2
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Discussion Starter · #3 ·
I appreciate the feedback! My train of thought lead me that last statement you mentioned, I should just buy a air compressor and start from square one because I already have a set of AC manifold gauges and most likely messed up on too many parts of the process. Im very uncertain that I got a proper flush when it was all put together at the shop.

Ester oil is what you are supposed to use with a r134a conversion, PAG isnt supposed to do well with the original mineral oil. You did say you had it flushed but that was with the whole system put together at the shop?

If the low side pressure isnt high enough the AC amplifier wont command the clutch to turn on, same goes with the high pressure switch.

6oz of any refrigerant isnt enough I would not go back to that shop just glad they only got $30 out of you. A quick search says the original R12 charge was 30oz so that means you should have charged 24oz of r134a.

You should spend the $200 or so and buy a vacuum pump and manifold gauge so you can do this yourself. Or you need to make friends with someone who knows what they're doing.
 

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If your A/C clutch isn't getting energized first check the fuse and ground. Next, is your 134 pressure right in the system? If your hole in the wall shop just drained and flushed and filled without checking for a leak your refrigerant may have leaked down to a pressure so low it won't actuate the pressure switch, which will interrupt the entire A/C circuit.
 

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91t gen5
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Get a real vacuum pump those air operated pumps can't get a deep enough vacuum for A/C work.

To add to that you need to have the vacuum pump running for around 15 minutes or more to boil out the moisture. I dont think your air compressor could maintain that.
 

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TopMR2: you need to fix the sensor on the frunk, it tells the AC amplifier that you have enough charge in the system to function. If the sensor is broken, it won't send power to the compressor clutch. It looks like the sensor is part of the tube, Toyota doesn't list a separate part number for it. You may need to source a replacement from another car.
 
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