I think I've got some electrical issues. My main problem is the apps. It probably needs to be replaced..but I'm trying to properly diagnose it, or if it's something bigger. 

 

Back story. The truck at all speeds has what I think is "dead pedal". 47re. When I'm taking off, the truck seems to go, then cut, then go..like it's not certain where the pedal is, even though I haven't moved my foot. 

 

The biggest problem for me is highway driving. I can't maintain speed with cruise control. If I reset the apps by unplug, key on reset, it'll work for a while, then fall off. If I set cruise control, at say, 65mph..rather than keeping a steady engine load of say, 20%, to maintain 65 on flat road..it will shoot you to 30% for a second, then drop to 0, then jump up to 25, then zero, etc..it's like it can't properly use or calculate what the appropriate engine load needs to be. 

 

I've tried cleaning grounds: pcm strap, passenger body, I've deleted and hard wired passenger battery ground disconnect, I've installed a bd noise isolator, mounted to that clean passenger side body ground. 

 

So ohm testing. I'm no electrician, but here's what I've found. I have a digital mm, on screen it sets m infinity symbol..I guess that is milliohms? (Is that even a thing)..when the truck is off, putting neg on pass battery neg, pos to alternator case, I get 0. However, on the body grounds, firewall pcm strap, and body ground with bd iso, I get 0.03. 

 

With the truck running..alternator case / block, it's still 0. However, body grounds and firewall ground to pcm go up to..0.16. Is this within spec, and what could cause such huge increase?

 

I have a nation's alternator, because my old one was leaking ac noise..this one however, is not. My black / tan is routed out to radiator, then around to battery. It is not wrapped in tin foil. 

 

I had my battery terminals replaced with military terms. (I asked for new cables too, but they retermed old..). Anyway, I've noticed some battery spill on both batteries. Passenger side new pos term has a tiny bit of corrosion, but the term itself has turned dark gray. I never had any corrosion on my old terms..and I did notice my voltage, temporarily in the morning, was higher than usual..not grid heater fluctuating, but constant. I felt the battery cables when I got home that day, they weren't warm at that time..but I feel like I've got some intermittent electrical issues I don't know how to identify properly. 

 

Oh, and my radio stopped working completely. It started off occasionally, then it would randomly turn back on once n a while..now it never turns on. It has power, lights, hitting volume turns clock on for a few seconds, then turns off again.

 

My blinkers, both sides, randomly stick on. I think that has to do with gauge installation tho..probably unrelated.

 

Jesus, sorry for long winded post..I hope someone can skim and help lol. 

Batteries are from 2015..had them load tested at an interstate battery store..said they were fine

10 minutes ago, dripley said:

Wired straight to battery, no fuse. The fuse does not protect the alternator any way. But I would have to to defer to electrically smarter than I to explain.

 

Thanks for that. I'm doing that mod this weekend so that info is great to have. Makes me wonder what the 140 amp fuse in the PDC box is suppose to do. Either way I like this mod.

Fuse does nothing after the mod. Unused. Only 2nd Gen trucks have a alternator fuse. Then 3rd gen trucks dropped the fuse idea.

10 minutes ago, Mopar1973Man said:

Fuse does nothing after the mod. Unused. Only 2nd Gen trucks have a alternator fuse. Then 3rd gen trucks dropped the fuse idea.

Yeah, kinda new after the mod the fuse would be useless unless you connected something to that post but just puzzling why C would design/install it in the first place. I also wonder it there is any benefit to running a additional wire (after doing the mod direct to the passenger battery) from the battery over the top of the radiator to the drivers side battery from the alternator. Thoughts?

Too much voltage loss not required.

2 minutes ago, Mopar1973Man said:

Too much voltage loss not required.

 

Thanks

14 hours ago, Mopar1973Man said:

Too much voltage loss not required.

I haven't done that part either, After reading W-Ts' article I thought it was to help the driver side battery absorb it's share of the ac ripple.

Edited November 10, 20186 yr by JAG1

The shrouded torches work very well, especially deep inside the engine bay close to other wiring/paint.

 

17 hours ago, rotohead said:

Yeah, kinda new after the mod the fuse would be useless unless you connected something to that post but just puzzling why C would design/install it in the first place. I also wonder it there is any benefit to running a additional wire (after doing the mod direct to the passenger battery) from the battery over the top of the radiator to the drivers side battery from the alternator. Thoughts?

You mean like this or a seperate charge wire from the alternator?

 

I woul almost think this wire does that, but this is from Sparky the Chicken's mind.

Edited November 10, 20186 yr by dripley

Correct. The heavy cable has way less voltage loss in the travel. This why the charge lead needs to be as short as possible. I cut off over 4 foot of cable and down to a mere foot or so of cable to the battery. A huge reduction in voltage loss in the run across the front of the engine back to the PDC.

29 minutes ago, dripley said:

You mean like this or a seperate charge wire from the alternator?

 

I woul almost think this wire does that, but this is from Sparky the Chicken's mind.

 

Yeah, I was thinking if there really was a purpose for the 140 amp fuse in the PDC it might be worth it to run another charge wire from the alt to the PDC but it seems that fuse doesn't do anything.

5 minutes ago, Mopar1973Man said:

Correct. The heavy cable has way less voltage loss in the travel. This why the charge lead needs to be as short as possible. I cut off over 4 foot of cable and down to a mere foot or so of cable to the battery. A huge reduction in voltage loss in the run across the front of the engine back to the PDC.

 

Make sense. I'm going to do that this afternoon. Thanks. I've got all new replacement battery cables and those nice battery terminal mounts from Genos Garage. Going to replace a lot of the OEM wiring and replace all the looms as they've all deteriorated badly. Looks like crap. 

1 minute ago, rotohead said:

 

Yeah, I was thinking if there really was a purpose for the 140 amp fuse in the PDC it might be worth it to run another charge wire from the alt to the PDC but it seems that fuse doesn't do anything.

 

@W-T got me thinking about the whole thing too. When you check back on the Dodge Ram truck history. 

• 1st Gen 89 to 93 - No alternator fuse.
• 2nd Gen 94 to 02 - 140 Amp Alternator Fuse in PDC
• 3rd Gen 03 to 07 - No alternator fuse.
• 4th Gen 07 to 18 - No alternator fuse.
• 5th Gen coming out in 2019. Most likely won't have an alternator fuse either.  

5 minutes ago, rotohead said:

Going to replace a lot of the OEM wiring and replace all the looms as they've all deteriorated badly. Looks like crap. 

 

You should see mine I still got all the OEM cables yet and excellent condition and never corroded once!

The inline fuse  was not meant to protect any increased amperage output from the alternator, but rather, to protect if the alternator develops a ground fault. Thats why the 140amp fuse allows your alternator to pass current up to it's max 136amp output.

 

When the alternator blows a positive diode, you now have the battery shorting to the ground faulted alternator - a couple 1000 amps with dual batteries - major fire hazard. Think overheated batteries + burning wires.

2 minutes ago, ofelas said:

The inline fuse  was not meant to protect any increased amperage output from the alternator, but rather, to protect if the alternator develops a ground fault. Thats why the 140amp fuse allows your alternator to pass current up to it's max 136amp output.

 

When the alternator blows a positive diode, you now have the battery shorting to the ground faulted alternator - a couple 1000 amps with dual batteries - major fire hazard. Think overheated batteries + burning wires.

 

So 3rd and 4th gen trucks have this possible fire hazard?

13 minutes ago, ofelas said:

The inline fuse  was not meant to protect any increased amperage output from the alternator, but rather, to protect if the alternator develops a ground fault. Thats why the 140amp fuse allows your alternator to pass current up to it's max 136amp output.

 

When the alternator blows a positive diode, you now have the battery shorting to the ground faulted alternator - a couple 1000 amps with dual batteries - major fire hazard. Think overheated batteries + burning wires.

4

 

 

 

9 minutes ago, rotohead said:

So 3rd and 4th gen trucks have this possible fire hazard?

 

So now search back on the internet and you find no such thing has ever happened. The diode will burn out like a fuse and that the end of it. The circuit is now open.

 

This is some terribly wrong information in the quote below. 

 

• 1st Gen 89 to 93 - No alternator fuse. 
• 2nd Gen 94 to 02 - 140 Amp Alternator Fuse in PDC
• 3rd Gen 03 to 07 - No alternator fuse.
• 4th Gen 07 to 18 - No alternator fuse.
• 5th Gen coming out in 2019. Most likely won't have an alternator fuse either. 

First gens have a fusible link in the charge wire to battery.

3rd & 4th gens - the TIPM has a fuse between it & one battery, whether driver's side or passengers side depends on single or dual alternator setups.

5th gen, 6th gen, any gen - will most definitely have some variation of ground fault protection in the charge circuit.

 

 

 

It's been some 15 years ago or so but I do remember 2nd gen owner(s) on another forum having to replace blown 140 amp fuses when trying to upgrade to higher output Alternators. I'm trying to find those old post but it's been awhile ago.

I'm thinking of adding one of those 200amp circuit breakers that are used in audio applications just as a precaution. What could it hurt?

1st Gen no listing of any fuse or fusible link... Dodge Factory Service Manual.

 

2nd Gen... Clearly shows the fuse...

 

As for 3rd gen and up I'll have to EAT MY WORDS... 

 

There is a fusible link but it in the loom somewhere. 

 

 

Edited November 10, 20186 yr by Mopar1973Man

14 minutes ago, rotohead said:

It's been some 15 years ago or so but I do remember 2nd gen owner(s) on another forum having to replace blown 140 amp fuses when trying to upgrade to higher output Alternators. I'm trying to find those old post but it's been awhile ago.

I'm thinking of adding one of those 200amp circuit breakers that are used in audio applications just as a precaution. What could it hurt?

 

A 200amp fuse won't prevent a battery shorting to ground, which in my battery setup, can be 2200 amps, and will blow a 140amp fuse just as easily as a 200amp fuse.

 

The charge circuit fuse should be rated just a bit above the max amperage a normally functioning alternator is capable of producing.

1 minute ago, ofelas said:

 

A 200amp fuse won't prevent a battery shorting to ground, which in my battery setup, can be 2200 amps, and will blow a 140amp fuse just as easily as a 200amp fuse.

 

The charge circuit fuse should be rated just a bit above the max amperage a normally functioning alternator is capable of producing.

 

So what do you suggest to avoid this potential fire hazard if I wanted to make it right?

11 minutes ago, Mopar1973Man said:

1st Gen no listing of any fuse or fusible link... Dodge Factory Service Manual.

 

2nd Gen... Clearly shows the fuse...

 

As for 3rd gen and up I'll have to EAT MY WORDS... 

 

There is a fusible link but it in the loom somewhere. 

 

 

 

LOL. You'll be eating your words again.

 

First off, that's not a 1st Gen Cummins FSM. It's a generic ChryCo diagnosis procedure is all, which doesn't show as much detail as a proper wiring diagram.

 

I will give you A for effort, considering you likely haven't worked on many vehicles other than your own.

 

Here is the fusible link on a first gen Cummins below. It's the 6ga BK wire in the middle of the page, which goes from the passenger fender shield along the firewall and then on the drivers side fender shield; the Hypalon is the fusible link, a few inches away from the BATT(+ve) post.

 

 

 

 

 

4 minutes ago, rotohead said:

 

So what do you suggest to avoid this potential fire hazard if I wanted to make it right?

 

If it's the existing factory 136amp alternator, keep the factory 140amp PDC fuse.