after driving 250 miles,i shut off van, completely dead nostart,no lights ,nada.tried pcm reset,swapped shutdown relay, eventually swapped out pcm,still nada!i have a new alternator being controlled by external voltage regulator.pcm not controlling and so have a 41 code but doesn't affect anything? new ignition switch. i am really stumped at this point.i pull out wiring harness behind brake booster[you know which wires,fuse links] i inspect the wires,don't see anything amiss. i casually try starting it and it starts! i drive for 4hrs straight to get home,no issues.at home it will no tstart,although this time i hear the fuel pick up,so sdr worked.next morning it starts no problem here is the thing,i drove out with one pcm and home on my backup pcm? i am open to ALL ideas. thanx in advance dawnbri

 

When it won't start, does the engine crank over, and just not fire? Or does it not even crank?

 

no it dosn't crank or turn over...completely dead

 

That's a heat soak problem. I'd check the positive and negative cables first off. Especially the negative ground cable at the frame or engine.

 

Since you're not getting lights it's either a bad battery, a bad battery cable, or the main power cable to the fuse box.

 

thanx for the grounding tip.i will run a jumper #6 from engine to frame.i have never heard the term heat soak before,could you tell me a little more about it please? thankyou dawnbri

 

alloro thanks for responding.i never checked to see if i had lights as it was midday when this happened.the battery is a couple of years old but appears to have a full charge upon testing,battery cable is 3ft long,visible and runs to connect all the fusible links for distrbution. does the +positive12v run thru the firewall connector directly to the ignition switch or to the fuses? i know there is another fused link feeding the fuse panel for blower and window feeds. thankyou dawnbri

 

The engine under the hood is basically an air and heat pump. Let's say you go out in the morning and it's 70 degrees outside. The truck has been sitting all night and is probably close to that. If you put a remote thermometer on everything under the hood, it will read close to 70. Let's say you run down the road to Anvils R Us because they have a sale and you want to add to your anvil collection. The engine has been running and getting up to temperature. Before it can cool off, you load your truck or van up with several nice heavy anvils. You live on top of a hill. That engine has to really work to get up the hill. You back up to the barn where you keep your anvils. Then you shut the engine off.

You come back a little later, maybe 20 minutes and use your remote thermometer. Everything under the hood is really hot now. The heat from the engine running under load is trapped by the hood and fenders. This is heat soak. Where it causes problems is wire resistance goes up with heat. If you have a battery cable that is corroded on the frame end, the resistance might be so high when you crank the engine, it can actually melt the little bit of metal that wasn't corroded. It can also be in components. A sensor or other electrical component has solder joints. If the solder is cracked, when it's cool, the unit will contract. As it heats up, everything expands. If there is a little bitty crack, that crack can expand and open the circuit.

I had a Dodge Diplomat that would stall at times. No rhyme or reason. Then I noticed if I left the hood open a crack to let air flow go over it, it ran okay. The brain box (engine controller) was bad. A 15 minute job, and that included getting the tools out and putting them up afterwards, and it ran like a top. Bench testing the controller showed it was good. Once it was hot, it failed because of heat soak.

 

ol'grouch thanks for your timely response,heat might have played a part as i was driving in the mountains up steep climbs for150miles.i have just finished adding a#4 ground cable from a frame member to an airpump bracket[unused]on the engine getting a secure bond.i think i still might have something else going on,wiring issues that may also be related to heat?thanks again for your input.iam desperately to stay part of the dodge family. dawnbri

 

41 Alternator field control circuit open or shorted

If it's not charging the battery it could be why you are experiencing problems.