LMTV A1 CAT 3126 circuit board power panel bad solder joints

[Suprman]

Got gremlins with your A1, with the circuit board style power panel? Intermittent electrical issues? My truck had relay sockets practically falling out. Its hard to tell unless you look carefully from underneath. There are traces on both sides of the board so it should be soldered on top and bottom. You cant see the top solder joints in most spots its covered by sockets. No wonder these trucks get a bad rep from the mechs this would be a hard problem to troubleshoot. It is repairable with a good soldering station and some quality thin 60/40 rosin core solder. You can carefully resolder the bad areas the solder should get drawn thru the back side to the top traces.

 

[scottmandu]

That was a silly design, hardly an improvement from the earlier panels. I love the PDM's on the C7... I wish there was a retrofit kit.

 

[profo]

Thats because they used the new and fancy RHOS solder crap that is the new lead free mandate in industry get some old 60/40 tin/lead solder to resolder and you will not have any problems anymore,

MArty

 

[Suprman]

Some spots have more of the conformal coating over the solder joints. I had to scrape away the coating before I could get good solder flow.

 

[MGKMartin]

Thanks for this information. I have a 2004 with some weird electrical issues. CTIS works great but the lights on the controller don't work. The bigger issue is that the top row of my main instrument cluster doesn't light up. Finally, the @$#@ low air alarm doesn't shut off until ~100 PSI. This truck came out of Ft. Irwin and is an 11th ACR truck with 2,500 miles so it shouldn't have this many issues. Oh well.. another adventure.

 

[Suprman]

My ctis lights came back when I swapped the power panel. Its a good place to start.

 

[tennmogger]

MGKMartin, my CTIS lights would not come on until I swapped out Relay 52. The socket had a 4 pin relay in it but needed a 12v 5 pin relay (type 3). Like yours, the CTIS worked fine, just no lights.

[edit: mine is a first gen, 1994, so may be different. Thanks to Suprman for noting differences]

 

[MGKMartin]

Thank you for letting me know about relay 52. I will check it out.

 

[Suprman]

The first gen and A1 relay scheme is different. You can interchange relays to see if the problem follows though. I would be careful not to pull out a relay and take the socket with it though.

 

[Rene M]

There is a company here in Houston that does that repair and wraps it with a lifetime warranty. This is not an exclusive problem, Ford, Gm, and several others are having the same issue on FICM and even radios.

 

[Rene M]

There is a company here in Houston that does that repair and wraps it with a lifetime warranty. This is not an exclusive problem, Ford, Gm, and several others are having the same issue on FICM and even radios.

http://www.seekspeedometers.com/

 

[Suprman]

Ive been playing with the bad board I have. A good scraping off of the coating then some light fine wire brushing and a good cleaning with alcohol before soldering is working good. I dont think there are any chemicals that will remove the coating without eating the plastics on the board also.