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loch bad wiring harness

remodel
remodel Member Posts: 68
has anyone else run into 1) a bad wiring harness on a loch 155 (2012 manufacture date) or 2) bad molex connector at the outlet sensor

Long story short, initial problem has reared its head again (the lockout is "OUTLET TEMP DIFF" lockout) I thought it was the outlet sensor so I replaced the sensor, it worked for about 10 months then I got the lockout again in the past couple of months. Next I thought it was the connector from the wiring harness to the sensor so I put some tape around the outlet sensor connection so the connector wouldn't sag but that only worked for 2 months.

I can actually shut the machine down in shutdown mode and wiggle the wiring harness and get the lockout which makes it seems like "short" somewhere. All the piping is in good shape and and she runs well when she runs.

Comments

  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Had the same thing on the short flat harness from the PCB. Could only get it to fire by putting pressure a certain way on the PCB connector. Checked all pins, to the eye, all seemed well. Rep Sent another PCB, but the problem is the harness. To be continued...
  • remodel
    remodel Member Posts: 68
    Thanks Bob, I am in contact with the rep so that's what I'll let him know. I was thinking the harness as well as the last time I got the lock out the connector was nicely secure. Its been frustrating and I am (not) glad you are having this problem as it vindicates my efforts trouble shooting this....I'll update as well once I hopefully get new harness.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    I reluctantly inherited this new install and right from the first cycle the harness connector made intermittent contact. Was able to "manipulate" things into contact, getting it to fire, but have not returned to change harness. Perhaps the client is dealing with original installer.

    like you, it took a while of poking and prodding and a few choice words to pinpoint the problem.
    Steve Minnich
  • delta T
    delta T Member Posts: 870
    I had this once on a loch KBN600 mysterious lockouts, different codes all the time, and finally replaced the whole wiring harness and all was well, has worked fine for years now. I think it was around that same mfg date too, maybe 2011, cant remember now. but as I said no problems since the new harness.
  • BobC
    BobC Member Posts: 5,306
    If this harness has molex connectors on the ends it could be a bad crimp on a pin, try moving each individual wire end to see if you can get it to act up. Also make sure they didn't crimp on a pin without stripping the insulation, I've seen that from time to time.

    Examine the pins and the sockets they mate with to see if there is any signs of corrosion, look for a green coating that happens when tin plated contacts see repeated contact with water.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • remodel
    remodel Member Posts: 68
    Thanks guys I'll check all the above again. No corrosion, but I'll check the crimp. I am temped to bend the pins to see if they make a better contact to female sensor connection (if that's the issue, which I don't believe is the case). I like the idea of messing with one wire at a time though. Trouble shoot this even further.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    In my case, to the naked eyes and "feel", the pins and sockets "seemed" ok. Only when put pressure on the plugged in molex, (to the right :)), I was able to get action.
  • BobC
    BobC Member Posts: 5,306
    Bean counters are always trying to shave costs. A decent quality bronze phosphor molex contact pin or socket used to cost about 20 cents, the cheap tin version cost 2 cents. Guess which one works best and then guess which one the bean counters go for?

    If one side of the molex connector is mounted on a printed wiring board, re solder the pins on the board and check for any cracks in the PWB near the where the pins are soldered.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • remodel
    remodel Member Posts: 68
    Still messing with this. Rep coming out to see if molex connector is bad. They do have wiring harness ready so we'll see. I was able to prop cables so the lockout has not happen for about 3 weeks.
  • rick in Alaska
    rick in Alaska Member Posts: 1,362
    I hate molex connectors. I have had a few do the same thing as you guys are saying. I currently have an older furnace that is experiencing problems and we have it traced down to the connection. I jammed toothpicks in to the molex connector and was able to keep it going. We are changing out the pc board in case the problem is there, but I am thinking it is the connector. Unfortunately, I can't get another connector, so hoping the board is the issue. Like the others have said, the connections look good, but my eyes are getting old, so who knows....
    Rick
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    It is incredulous this is happening when you think of, say, the millions of motorcycle and automotive molex applications out there subjected to way harsher environments. It's really disturbing.
    RobG
  • bmwpowere36m3
    bmwpowere36m3 Member Posts: 512
    Bob Bona said:

    It is incredulous this is happening when you think of, say, the millions of motorcycle and automotive molex applications out there subjected to way harsher environments. It's really disturbing.

    True... but in my experience "multi-pin" connectors in vehicles are of a much higher quality and "weather-proof" as compared to those typically found in electronics or consumer devices.

    Working in the aerospace industry the only "nicer" connectors I've worked with are the MIL MS cannon ones... very, very nice, but spendy.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    edited May 2015
    Yes, I've been pleased with some of the weather proof connectors I've dealt with on modern vehicles.

    Come to think of it, in my previous life as a Honda tech and service mgr, I recall the 85 Gold Wings did have a problem with thier 3 spade molex style connectors from the stators. They had poor connections and would melt the connector and if not caught soon, the stator would follow. An ugly job bc the engine had to be removed for the repair. If i remember correctly the fix was an updated connector and dielectric grease.
  • BobC
    BobC Member Posts: 5,306
    @bmwpowere36m3 I remember a series of plastic Amp connectors in the early 80's that were pretty good and not to spendy. The key was they used good quality contacts, not gold plated, but very reliable.

    We used thousands of them on mil power supplies where the govt decided to cut costs by allowing their use.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • remodel
    remodel Member Posts: 68
    Well rep came out to ohm the sensor (senor is good, which we all know) and I could not reproduce the fault for the rep. ...ah darn. But I was able to reproduce it at a later time (like after he left). I have not had the problem again since I tied a zip-tie real tight and it is somewhat holding the connector in the sensor real well. It is a problem for sure with the molex connectors. I don't want to buy another wiring harness so I will ride this out for a little bit. Pretty lousy though as it seems to happen a little randomly as well.
  • remodel
    remodel Member Posts: 68
    Well rep came out to ohm the sensor (senor is good, which we all know) and I could not reproduce the fault for the rep. ...ah darn. But I was able to reproduce it at a later time (like after he left). I have not had the problem again since I tied a zip-tie real tight and it is somewhat holding the connector in the sensor real well. It is a problem for sure with the molex connectors. I don't want to buy another wiring harness so I will ride this out for a little bit. Pretty lousy though as it seems to happen a little randomly as well.