Recall that the FICM in my bus is starting to decline - now it's at 40v when first started. Still gets to 48v after warmup and all the time when driving. Since I've made it back to warmer climes, it starts fine and idles smoothly.

My question: it looks like replacing the power supply is pretty easy and not too expensive. What are the chances that would fix me, or is there any way to diagnose the logic board if it's the problem? I'm not getting a 611 code.

 

Any number of issues can cold soak / load down that FICM........component performance on the power supply being just one, connections being another, harness, other elec being another set of considerations...........

Need to instrument/record to track its performance before throwing parts at it

 

Thanks, 1990. Agreed, it's important to first fix whatever caused the FICM to lose power. I'm thinking it's been caused over time by low battery voltage. I've had the truck die while driving due to bad battery connections, and they seem to lose voltage while parked, like something is draining them. I got a 1318 low voltage code this week. It's prolly the cables. The batteries are relocated by the aftermarket mfg and don't use OEM cables. They're also 15 years old now. The PO had "repaired" one of the terminals by cutting it out of the daisy chain and using a standard auto parts store terminal in its place. Unfortunately, those terminals are made to accommodate the two input cables of a daisy chain, so they only had half of each cable's wires in the clamp. I couldn't find a double terminal locally or with a quick google and simply did the same thing a bit better. Time to do a better google.

This truck also has multiple harness issues. I've already replaced all the trans harnesses, and taped up the engine harness to the EOT/EGR/Fan, but I still get an EGR code. I've decided to part out my Red Cross ambulance (sigh, my favorite truck) and will be scavenging all of its harnesses to replace these. Other issues are no dash lights and no cig lighter power. Maybe that's just fuses, but based on the rest, I expect not.

I have swapped in another FICM from my other ambulance (the Red Cross ambulance is stored in Dallas), and it's again running fine. The 1318 cleared. I'm getting 14v on my Torque and the batteries are less than a year old, so I'm hoping I'm good for now.

That brings me back to the old FICM - my original question. I want to fix it and replace it back in that ambulance. Based on the above, and no FICM codes ever showing, I'm thinking it just has a bad power supply, but wanted to know if there is anyway to confirm that the logic board is good. Perhaps a visual inspection for burnt connections on the logic board?

 

I reckon FICMrepair should reply to this - what's best?

 

Not sure they want to encourage self-repair, but maybe they sell the power supply by itself.

 

FICMRepair will repair your old unit. Or send you a rebuilt unit in exchange for yours. Check out their site. B.

 

Thanks, LB. Yes, I have used their service before and for other parts. Very good folks. However, if all my FICM needs is a power supply, those are simple to install and readily available from many vendors. If FICMRepair sells that, I would feel very confident buying from them again. Just don't want to spend $400 if all I need is a $40 part.

Unless I hear some reason not to, at this point I'll prolly just roll the cheap dice and buy that part and see if it fixes the problem.

 

I can't tell you if there is a way to test the supply but I did replace my power supply when my voltage was dropping below 47.

That was over 4 years ago and I have not had any drop offs since then.

In my case the power supply replacement worked and I didn't need to repair/replace anything else.