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#11
Mechanicals / Re: A/C compressor confusion? ...
Last post by daantjie - 15 April 2024, 09:44 AMUnfortunately it's very hard to get to without essentially stripping out the dash. It sits under the dash and probes the evaporator temperature with a capillary tube.
#12
Mechanicals / Re: A/C compressor confusion? ...
Last post by 79W116 - 15 April 2024, 07:56 AMWell, this morning I tried jumping the pressure switch together to see if that would get the clutch to pull in, but it did not. I had the car running, full cold on the dial, A/C switch on, and Auto High.
Where is the "ETR" switch located?
Where is the "ETR" switch located?
#13
Mechanicals / Re: A/C compressor confusion? ...
Last post by daantjie - 14 April 2024, 08:00 PMBefore removing the switch I would take it to an AC shop and have them test the high and low side pressures to see if you're in range. I would assume switch failure to be an outside chance but I would start with pressure testing first. You may have a leak in the system which the shop can check for which would have to be tended to before anything else.
#14
Mechanicals / Re: A/C compressor confusion? ...
Last post by 79W116 - 14 April 2024, 07:13 PMQuote from: daantjie on 14 April 2024, 03:53 PMIf you bridge the terminals for the pressure switch at the drier then the clutch should engage, as the pressure switch is a safety feature to not engage the clutch with a low gas charge. There is an "ETR" switch which also locks out the compressor under a certian temp reading to privent freezing up, but I'm guessing your current ambient is higehr than the cut - out so I doubt this is your problem.Ah OK, I'll try to bridge then and see if that works. So if the clutch does engage then I'm replacing the pressure switch then, correct? Which means having a shop remove all r134, replace switch, then recharge, right?
#15
Mechanicals / Re: A/C compressor confusion? ...
Last post by 79W116 - 14 April 2024, 07:10 PMQuote from: rumb on 14 April 2024, 04:43 PMProbably some helpful info here:yep, I've been buried here for a few days for sure, just just say test everything in this order. I'm just not the best with a schematic and thier generic list. Was hoping for someone to recognize my condition.
https://handbook.w116.org/Climate/
#16
Mechanicals / Re: A/C compressor confusion? ...
Last post by rumb - 14 April 2024, 04:43 PMProbably some helpful info here:
https://handbook.w116.org/Climate/
https://handbook.w116.org/Climate/
#17
Mechanicals / Re: A/C compressor confusion? ...
Last post by daantjie - 14 April 2024, 03:53 PMIf you bridge the terminals for the pressure switch at the drier then the clutch should engage, as the pressure switch is a safety feature to not engage the clutch with a low gas charge. There is an "ETR" switch which also locks out the compressor under a certain temp reading to prevent freezing up, but I'm guessing your current ambient is higher than the cut - out so I doubt this is your problem.
#18
Mechanicals / Re: 280SE engine mounts
Last post by daantjie - 14 April 2024, 03:48 PMI would suggest to spring for original Mercedes parts on engine mounts to be honest. I have had bad experiecnes with aftermarket rubber parts in general, and especially on engine mounts, thus I woulde suggest Benz parts only, even though it will be quite pricey, basically "buy once, cry once"...
#19
Mechanicals / Fuel System Questions
Last post by sbetts - 14 April 2024, 03:34 PMReading about the costs under "Common Fail Points And Fixes" in the article below makes reworking a D-Jetronic system that has been sitting for 20 years a bit financially daunting.
What is the likelihood that I'll need to replace the Engine Control Unit, Manifold Pressure Sensor, or injectors? Are the costs actually that high for parts? Can I refurbish these parts instead or replacing them?
https://www.hemmings.com/stories/your-quick-guide-to-the-bosch-d-jetronic-k-jetronic-and-ke-jetronic-fuel-injection-systems/
What is the likelihood that I'll need to replace the Engine Control Unit, Manifold Pressure Sensor, or injectors? Are the costs actually that high for parts? Can I refurbish these parts instead or replacing them?
https://www.hemmings.com/stories/your-quick-guide-to-the-bosch-d-jetronic-k-jetronic-and-ke-jetronic-fuel-injection-systems/
#20
Mechanicals / A/C compressor confusion? 79 3...
Last post by 79W116 - 14 April 2024, 01:44 PMI'm sure for a few of you experts out there this will be an easy one, but I am stumped!
I purchased my '79 300SD about 5 months ago, and an indy dealer switched it from R12 to R134 at that time with the PPI and other work before I got it to my house. It worked fine as a quick test when i got it, but was winter of course here in Michigan.
I installed the Hamilton upgrade kit a few weekends ago and now everything works, except the compressor. Although since its been winter and I don't know if its worked in the last 3 months cause why would I have it on in 20 degree weather.
The switch on the main panel in the center console broke recently (spring housing gave way on a corner), but luckily i found out that i can just flip the front toggle upside down and flip the "on" and "off" inserts and ball and spring, and it tests fine with my multimeter.
Next, i had a separtate motorcycle battery that i tapped the leads directly to the A/C compressor and the clutch worked great everytime it got power.
From the receiver-dryer hooking the blue with green wire from the pressure switch to the blue wire from the temp switch makes the fan go on fast and constant, but not the clutch engage. and hooking up the red with green and blue (pressure switch) to the blue wire on the temp switch makes the fan go on in cycles (surging on and off) but again, no clutch engagement.
I tested both fuses that are dangling in the fuse box area, and every single fuse in that little box as well. All good.
I'm sure this is an easy one that I'm missing, please someone tell me what my next step is. I would be very appreciative.
I purchased my '79 300SD about 5 months ago, and an indy dealer switched it from R12 to R134 at that time with the PPI and other work before I got it to my house. It worked fine as a quick test when i got it, but was winter of course here in Michigan.
I installed the Hamilton upgrade kit a few weekends ago and now everything works, except the compressor. Although since its been winter and I don't know if its worked in the last 3 months cause why would I have it on in 20 degree weather.
The switch on the main panel in the center console broke recently (spring housing gave way on a corner), but luckily i found out that i can just flip the front toggle upside down and flip the "on" and "off" inserts and ball and spring, and it tests fine with my multimeter.
Next, i had a separtate motorcycle battery that i tapped the leads directly to the A/C compressor and the clutch worked great everytime it got power.
From the receiver-dryer hooking the blue with green wire from the pressure switch to the blue wire from the temp switch makes the fan go on fast and constant, but not the clutch engage. and hooking up the red with green and blue (pressure switch) to the blue wire on the temp switch makes the fan go on in cycles (surging on and off) but again, no clutch engagement.
I tested both fuses that are dangling in the fuse box area, and every single fuse in that little box as well. All good.
I'm sure this is an easy one that I'm missing, please someone tell me what my next step is. I would be very appreciative.