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Hi all
95 850 question
Bought used last month. Car runs great and AC works
Going thru the car to see what it needs, I noticed the 2 single white barrel connector leads off the AC compressor senor (overheat senor??) have been unplugged.
AC works though.
I do see the single connector coming off the alternater is connecting.
Was something bypassed?
Thanks
Rob
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Without looking, I would guess the temp sensor has been bypassed. Check the clutch gap. Make sure it cycles a lot when the cabin temperature drops down to the dialed in temp setting. The cycling will keep the compressor cool.
Klaus
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There is no present time, just the past and future
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will do,
Funny thing is I don't know how to hook back up....no addtional harness to connect to...will need to dig deeper into this one
thanks for now
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I don't think you will have any problems with the current set up. If you are dying to get back to stock, I suggest a visit to a pick&pull yard and see if you can find the wires. There might even be some extra finds...
Klaus
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There is no present time, just the past and future
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Ok, now I understand the wiring.
A single lead comes out from a harness wrap. It has been plugged direclty into the clutch lead on the compressor.....the two temp sensor leads off the back of the compressor are disconnected.
So origianl wire routes is?:
single lead coming out of harness wrap goes to the matching socket lead to temp sensor.....then the second temp sensor lead goes to single clutch lead?
Why would someone do this by pass in the first place? What could have been wrong?
thanks
Rob
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What happens is the clutch gap gets too wide to work when the compressor heats up, so the AC does not engage. A few years ago, people thought that the reason the clutch did not engage was because the thermostat at the compressor was disabling the compressor. Ergo, disable the tstat and you then have AC again, especially on very hot days.
This might have worked, but in most instances it was the clutch gap in excess of .040 inch. The bread clips fix all of that.
Klaus
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There is no present time, just the past and future
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ok
What do you mean the bread clips fix all that?
Do I try to fix it? ...and if so how can the gap be adjusted or is it a matter of worn out plate material?
Thanks klaus
Rob
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Because the compressor is cycled a lot, the clutch plate wears. When the gap exceeds .040 the electromagnet is no longer strong enough tto pul the clutch in. This happens when the compressor gets warm. Once it cools, the clutch will work again for a little while.
The real repair is to remove the clutch and move the shims to get the correct gap. It is much easier to shove a bread clip, about the correct size, under each of the 3 studs. This reduces the gap and makes the clutch work again.
On my 1998, same system, I used some thin aluminum instead of the plastic bread clips. A little glue held them in place and the AC was working as new. It did take me an hour to do, but I am anal: measure the gap before and after, then apply glue to the strips and insert and measure the gap again - .20
Klaus
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There is no present time, just the past and future
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Ok....getting closer to warmer days in Cali Valley. Needed AC today.
The compressor wiring is still bypassed as spooken in the thread. I did plug the wires back together as it should.....and the ac clutch did not engage.
I put the wires back as prior...and now it engages. So something with the little sensor on back of the AC....what does it sense?
Today, while needing AC, it turns on cold but within about 5 minutes, the cold temp goes down. I turn the cabin AC switch off for a while, and then turn back on, it gets cold again and then slowly goes back down in temp.
I pulled fault code from box B term 1
I get:
2 1 1 driver side damper position sensor open circuit or shorted to 12v
3 2 1 driver side damper motor active too long
4 1 4 driver side interior temp sensor inlet fan seized
So what do ya all think?
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The cabin temp sensors are behind the strap handles above both front doors. The driver's side does not work, so remove the handle and pull the sensor out carefully and clean it. I used a wooden toothpick to get the dirt off the little fan blades.
Clear the codes on B-1, the damper motor cannot be shorted out and running too long at the same time.
Check the clutch gap on the compressor, if it is .040 or greater, the clutch will not engage when it gets hot.
I do not understand the temp getting 'lower'. You mean colder? Where is the temp dial set at? Is it the same for both sides of the car.
Are the blower speed and vent selector both set to AUTO? If the yellow lights blink, the ECC will not work in automatic setting, you will then have to set your own fan speed - never at zero.
Klaus
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My name is Klaus and I am a V ♂ lv ♂ holic
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Thanks Klaus,
oops, I meant the as-time goes by with AC on, the air goes from nice cool to warmer (matching outside vented air temp)
I had both temp dials to 60 degrees (all the way CCW), vent dial to 'face' vents, fan to mid speed level.
Yes both REC and AC lights blink after starting car....to indicate fault.
I cleared codes and then error 2 1 1 re-establishes right after clearing.
I am gonna do the bread clip trick.
Also, where is the evap drain tube outlet?...I would expect to see water drips with AC on in driveway. I would like to clean the tube out. Is it right above the heat shield over exhauest pipe?
Thanks again for sharing your experience.
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The drain tube is smack center of the tranny tunnel, just behind the firewall. A most inhospitable place to get to!
Do the bread clip first. Insert one and check the gap with a feeler gauge. If good, then apply glue to both sides of the clip and insert all 3. You want at least .020 clearance and not more than .030
The 2-1-1 is a royal pain. The dealer wants $250+ for one of those stupid motors. Find a pick&pull for a replacement. The motor in question is on the driver's side above the gas pedal. Do not connect 12V to the motor as a test, that destroys the park position sensors.
I do not envy your having to be upside down and backwards. A folding torx tool works best.
Klaus
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My name is Klaus and I am a V ♂ lv ♂ holic
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nice Klaus,
FMI, what does the 2 1 1 related motor do? What would be the HVAC distribution symptom...not heat to feet in driver foot well?....AUT will not function in some way?
I plan on not fixing it, if not affecting AC temp
I don't like the AUT system anyways...I like to control things....habit from 7401/940 past.
Rob
95 855T
90 MB 300E
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If you don't need heat on the driver's side, or a little cool air down on your feet in the summer.
Too bad, the ECC system is one of the best in the world. I found setting the temp to 78F in the summer and 74F in the winter perfect, and the car always kept it there. This is not some junky system, you really don't want to set the temp to 60F in the summer and 80F in the winter, constantly turning the dial when the sun shines on the dash and heating up one side of the car.
Besides, when it is cold out, the blower does not run until there is some heat in the antifreeze. And then the blower comes on gradually as the coolant gets hotter. Just the opposite for AC, the blower comes on strong and slowly decreases as the air in the cabin cools. Initially, the AC turns the vents to the dash and slowly opens the foot vents as the air cools down. Just perfect.
If you have driven American iron/plastic, you will note that AC only works when the air comes out of the vents, and is mixed with heat later because the compressor is always on.
Klaus
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My name is Klaus and I am a V ♂ lv ♂ holic
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The super glued bread clips worked and the compreesor is wired correctly with the temp sensor.
Another thing to add, don't know if glue on both side of clips is a good idea.
If glued on both sides, it prevents the 'clapping' effect of the clutch plate.
With the clips now glued to face of plate and face of existing white round shims, when the clutch engages, now the existing round white shim pulls through its mount hole. I got too much glue on and some got on the existing white shim mount holes....therefore not allowing the clutch to engage. I had to pry the plate closed to free the existing shim mount free (break the glue) of the outside plate.
So now the existing existing plastic white shims pull through their mount holes when AC is on.
Nice work...and thanks BB
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