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  1. R

    Trying to identify a key-on switched circuit, dashboard fuse box, '13 3500HD LML

    wiring diagrams in the ELECTRICAL MANUAL for your truck and model https://www.gmupfitter.com/pages/body-builder-manuals I didn't look to see what is available for your truck, but on my 2008 mode there is a fuse block near the brake pedal called MBEC and there are likely open. Also, look for...
  2. R

    Looking for help with P0335 and P0336

    See attached on P0335. Note that this is for my 2008, your pin #'s may be somewhat different. Do you have a scope so that you can monitor the signals real-time? And it looks like it could be the ECM. Make sure you have tested thoroughly before buying expensive parts.
  3. R

    LB7: Electrical gremlins and I have no idea where to start

    See links in post #7. Also, there are videos on Youtube about locating the ground point near the front dash speakers, well worth the time to watch a couple of them.
  4. R

    ABS Pain

    Lots of Youtube videos about checking wheel speed sensors, including cross-checking the wiring between the sensors to find the bad sensor. I like the ones by South Main Auto because he explains better than most why he is doing the procedures.
  5. R

    Could a BCM cause this?

    Get the Electrical Manual for your vehicle here: https://www.gmupfitter.com/pages/body-builder-manuals. These have a section bout RAP and a general outline of the electrical starting system that may be helpful
  6. R

    100k miles, internal filter change?

    It is not necessary, but I would drop the pan, change the internal and external filter, and to a complete change to a TES-295 using the HOOT method. You don't know what you don't know (you don't have any history on the truck for the trans) so the price to do this work is minor compared to what...
  7. R

    Wipers turn engine off...

    Yes, wiper motor or arms are contacting something which shorts out wiring/ground. Play around with it, keep looking until you find it and can repeat the problem. and you'll find it.
  8. R

    2006 3500 express van turbo diesel cooling system

    Regarding your question about a 20 lb cap, I have been running a 20 lb cap in my 2008 LMM for several years now without any problems. Are you sure your 15 lb cap is really holding 15 lbs?
  9. R

    2009 better MPG

    You should be getting better than 11for general driving, town and highway combined. If you take your truck on a long drive, say 5-8 hours, does your MPG improve for a few days at least? If so, I would carefully check DPF and converter (DOC) to see if plugged when not on long trips. While your...
  10. R

    LB7: 2001 5 speed allison tcm ground issue. in need of ground wire diagram of body harness

    Wiring diagrams available here: https://www.gmupfitter.com/pages/body-builder-manuals. Look for the ELECTRICAL MANUAL for the year/model of your truck.
  11. R

    2016 LML intermittent gauge loss and no crank, no start

    You have a circuit problem somewhere. Definitely not easy to find unless you can get your truck to exhibit the problem while you are troubleshooting. Shaking the harness underhood going to the Instrument panel would be the first thing, then maybe the TCM to trans harness would be another, then...
  12. R

    LBZ, LMM MAF??

    Those sensors appear to come from gasoline engines.
  13. R

    2008 LMM dual alternator idler

    Use your VIN# and go to a GM based website and do the parts lookup. I would GUESS that it is the same, but you never know unless you verify the correct part number..
  14. R

    Alternator lead?

    Free wiring diagrams (sometimes connectors also) at https://www.gmupfitter.com/pages/body-builder-manuals
  15. R

    LMM Mega Fuse Wiring Layout

    See Attached
  16. R

    Brakes and Power Steering Dead

    There is a valve on the outlet side of the pump that sometimes fails to operate properly. Go to a GM-based parts lookup and look at the junction between the pump and the outlet hose. There are many posts about this on some diesel forum sites, usually because people with large tires can't turn...
  17. R

    Another PSC install along with 2011 hydroboost and all new PS lines.

    Nice work and pictures. Thanks for posting.
  18. R

    Moving to Phoenix, AZ

    The VA hospital is at 7th ST and Indian School RD. If you were to drive north on 7th ST between Camelback RD and north to the Canal, there are lots of moderately priced homes and good schools. The best thing is to call a Realtor with your price range and what type of home you would like (as long...
  19. R

    Brake controller

    Yes it does, at least for my 2008 model. Go here and find the Electrical Manual for your year/truck model and I'm pretty sure there will be information about this. https://www.gmupfitter.com/pages/body-builder-manuals
  20. R

    Brake controller

    Is the controller being fed by a 12V circuit? Test to be sure you have 12V going into the controller.
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