Hi, All! This is a great forum! Lots of help and great posters. Thanks for having me. I am a New user, of course, and I have an L555 issue! (Imagine that!?) PLEASE! ANY HELP would be GREATLY appreciated! Thanks! I have been researching and troubleshooting this problem for 10+ days now, and I am stumped,... and running out of ideas,... and time,... This is a new post about an old issue,... There are other posts about this, but none of the ones I read seemed to correct my problem. Here are the details,... (Yes,... I am anal about details! The Nuclear industry made me that way,... sorry!) I purchased a 1990 New Holland L555 Deluxe from a dealer 7 years ago in 2010. I don't use her every day, but I push snow in winter, rake gravel in summer, move pallets of fire wood and coal for heat, and do some light excavating, all at my own house / barn,... no commercial work. She had 3830 hours on her when I got her, and now has 3867. This unit was a trade-in from a golf course, where she served since new, so the hardest thing she probably ever did was move sod,... in other words, she isn't beat to death like a red-headed concrete / paving machine! Shes has been running perfectly since I got her,... until last week, that is. Now, all the sudden, the boom and bucket won't function for more than a couple moves before the SOL LED light on the module goes out. If I shut the machine down, and re-start it, it will function again, but still only for a few manipulations,... then the SOL LED goes out again! All other control LEDs seem to function correctly as specified. I researched all the info I could here on this forum (and elsewhere), so my first troubleshooting attempt was to test the seat safety switch harness with the diode/resistor. Without the engine running, I was getting 12.8v upstream at harness connector to seat, but at the downstream side of the resistor, to the control module, I was getting 12.2v, a drop of only .6v rather than the specified drop of 1.2 to 1.6v. Based on the forum info, I replaced the harness @ $70 + tax + s&h, from Messicks. I also double-checked both seat safety switches which seem to be making solid contacts, and the seat-belt safety which also seems to function correctly. Well, replacing that seat safety harness didn't work! I still have the same issue, although I have discovered that when I reduce the engine RPMs to bucket will function again, briefly OR as long as the RPMs are < 25%. I also noticed that the hydraulic charge light would intermittently "flash" on for a second once in a while especially when I was operating the bucket/boom on "high," so next I checked hydraulic oil level, which was about 2.5 gallons low due to a very small chain-case cover leak. I added fluid to correct level, but still have the same SOL LED issue - won't stay lit above 25% engine RPMs! Per further research, and suggestions of possible clogged filters, I have ordered all new filters, and will change them out as soon as they arrive. However, the hydraulic fluid is crystal clear (because I add a gallon or two a year due to that small leak, described above) so I am not leaning in that direction, but rather "poking and hoping" right now,... trying to resolve this "gremlin" as quickly and correctly as possible for the least expense. OK, guys,... What else can I look for to troubleshoot this SOL LED Gremlin? It seems strange that for 7 years it ran fine, then all the sudden, BANG! SOL/LED control box issue? This makes me think the control logic box is the issue, but if so why are the RPMs affecting its operation? The RPMs affecting it is making me think the hydraulic pressure / flow could be the issue,... Is there another way to test the control box function? As per the detailed instructions in previous posts here, I have verified all the other control box LED lights function correctly for order and sequence,... I read one post that a guy "jumpered" the 12v out of the seat safety switch directly to the SOL Valves as his SOL LED output was only 2v, but I am assuming his SOL LED light was "ON" but control was malfunctioning, not outputting the correct 12 volts? I can (and WILL) jumper 12v to the SOL Valves if the control module is bad, ($700 for re-manufactured unit!!!) but I would only to that as a last resort. I work in the Nuclear industry and BELIEVE in safety (unless it costs too much!) so I would rather have the safety features function correctly if possible,... and I don't want to damage my pumps if it is a hydraulic issue. What should the control output voltage to the boom / bucket SOL Valves be? Or doesn't that matter if the SOL LED is OFF? Why would the SOL LED on the module function at
