AC Control Unit & Tranny Fluid in Wiring Harness
05-27-2009, 01:39 AM
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1998 E320 Sedan
AC Control Unit & Tranny Fluid in Wiring Harness
I have a 1998 E320 (W210) and my qualified and honest mechanic says my AC Control Unit (in dash control buttons) has gone bad. He has been able to find a quality rebuild with 3-year warranty for $500 plus $400 labor (includes diagnostics to find problem).
Today he called to tell me that while tracing the wiring back, he noticed that there was tranny fluid inside the wiring harness. Seems a connection to the transmission had a seal fail and injected fluid inside the harness. Normally, he says, there is leaking around the seal, but for some reason no fluid was seen, so he could have easily overlooked this issue.
Now, he says he will need to find the harness (maybe another $500 plus labor) before he can get the whole job done.
Questions:
1. Has anyone heard of fluid forced into wiring harnesses, particularly the one connected to the tranny?
2. Is a quality (non-Ebay, not an unknown reputation) control unit for the dash cost $500?
3. The car has 151,000 miles, runs great, new tires, new brakes, garage kept, second owner, very, very clean worth spending another $2,000-2,500 and hope to get another 3 years of service??
Thanks for all your responses....
Knucklehead
Today he called to tell me that while tracing the wiring back, he noticed that there was tranny fluid inside the wiring harness. Seems a connection to the transmission had a seal fail and injected fluid inside the harness. Normally, he says, there is leaking around the seal, but for some reason no fluid was seen, so he could have easily overlooked this issue.
Now, he says he will need to find the harness (maybe another $500 plus labor) before he can get the whole job done.
Questions:
1. Has anyone heard of fluid forced into wiring harnesses, particularly the one connected to the tranny?
2. Is a quality (non-Ebay, not an unknown reputation) control unit for the dash cost $500?
3. The car has 151,000 miles, runs great, new tires, new brakes, garage kept, second owner, very, very clean worth spending another $2,000-2,500 and hope to get another 3 years of service??
Thanks for all your responses....
Knucklehead
05-27-2009, 10:14 AM
#2
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In late 97 and early 98 there were 2 or 3 revisions to the trans harness oring seals. Known issue that allows fluid into the harness. Danger is it wicks up to the ECU and fries it.
The CCU pops out with radio keys and then snaps back in place. There is some minor binary coding required. Don't understand why it would require so much labor. What is the AC system doing, or not doing and whats been done previously.
The CCU pops out with radio keys and then snaps back in place. There is some minor binary coding required. Don't understand why it would require so much labor. What is the AC system doing, or not doing and whats been done previously.
05-27-2009, 08:56 PM
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1998 E320 Sedan
Thank you for your fast response!
I first took the car in because when I turned on the A/C, it would blow cold for about 1 minute then it would go to ambient temperature. Thinking it was just in need of freon, I scheduled an appointment.
My mechanic did some diagnostics and found the control unit to be faulty. He also says that the clutch looks a bit 'burned' but was unclear if it was too damaged to replace. The compressor would continue to recycle and he felt it was overdoing it.
He found a reputable company that rebuilds control units ($530) with a 3-year warranty. When he installed it, he stated that the display was not working well. (Perhaps this was due to the fluid in the harness he discovered later on).
He began to test the harness and noticed tranny fluid had crept up into the wiring. He stated that normally he would notice a bad seal due to leakage, but in this rare case he did not. Tranny fluid was not leaking out, but simply injecting into the wiring harness.
He sent the control unit back (thinking it was the display that was faulty) and is researching prices on the harness. He suspects it will cost about $1,000 in parts (harness and control unit) plus $400 in initial labor; plus labor to install the harness.
Does any of this sound right to you? How much would you suspect it would cost to replace the harness??
Your opinions greatly appreciated!!
I first took the car in because when I turned on the A/C, it would blow cold for about 1 minute then it would go to ambient temperature. Thinking it was just in need of freon, I scheduled an appointment.
My mechanic did some diagnostics and found the control unit to be faulty. He also says that the clutch looks a bit 'burned' but was unclear if it was too damaged to replace. The compressor would continue to recycle and he felt it was overdoing it.
He found a reputable company that rebuilds control units ($530) with a 3-year warranty. When he installed it, he stated that the display was not working well. (Perhaps this was due to the fluid in the harness he discovered later on).
He began to test the harness and noticed tranny fluid had crept up into the wiring. He stated that normally he would notice a bad seal due to leakage, but in this rare case he did not. Tranny fluid was not leaking out, but simply injecting into the wiring harness.
He sent the control unit back (thinking it was the display that was faulty) and is researching prices on the harness. He suspects it will cost about $1,000 in parts (harness and control unit) plus $400 in initial labor; plus labor to install the harness.
Does any of this sound right to you? How much would you suspect it would cost to replace the harness??
Your opinions greatly appreciated!!
05-28-2009, 01:41 AM
#4
Super Member
My diesels harness was replaced; first had to fly here from the fatherland. Harness was $600 at the dealer. Labor as I recall was 2-3 hours. Was not my dime so let it happen.
The harness and AC ought to be unrelated.
Wait for one of the techs or someone more knowledgible to respond before doing more. Doesn't sound quite right to me.
You can pull up the actual values for the AC and the error codes using the CCU. Thats always the frist step unless the comp is frozen. You might have a restriction or bad sensor that disables the comp???
The harness and AC ought to be unrelated.
Wait for one of the techs or someone more knowledgible to respond before doing more. Doesn't sound quite right to me.
You can pull up the actual values for the AC and the error codes using the CCU. Thats always the frist step unless the comp is frozen. You might have a restriction or bad sensor that disables the comp???
06-05-2009, 06:37 AM
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2003 E320 4Matic Wagon & 1997 E320
About the transmission. Is your car in limp mode or it shifts fine? If it shifts fine, then do not let him replace the transmission control unit. There are multiple names for this thing (ETC, EGS, TCU, TCM) so make sure it is under the black plastic cover, on the passenger side, near the firewall. It is next to the K40 module.
If it is not shifting, then still do not let him replacing the ETC. The ETC is designed to shut off power to the transmission solenoids once there is trouble codes in it. Once the trouble codes are cleared, the ETC will most likely function again.
The connector that leaks for the harness is less than $10. There are two O rings so it depends on which one is leaking, you may or may not see fluid leaking to the outside. Do replace this part and clean the harness and the ETC, if there is fluid in it.
Does the mechanic have equipment to clear transmission codes? They cannot be cleared with OBD II scanners.
If it is not shifting, then still do not let him replacing the ETC. The ETC is designed to shut off power to the transmission solenoids once there is trouble codes in it. Once the trouble codes are cleared, the ETC will most likely function again.
The connector that leaks for the harness is less than $10. There are two O rings so it depends on which one is leaking, you may or may not see fluid leaking to the outside. Do replace this part and clean the harness and the ETC, if there is fluid in it.
Does the mechanic have equipment to clear transmission codes? They cannot be cleared with OBD II scanners.
08-23-2011, 03:31 PM
#6
Senior Member
I know this is an old post but is there a DIY for the replaceing of the transmission piece that allows the fluid by. I have this problem and would like to attempt myself
