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K.I.S.S.I started to get the infamous loc unloc syndrome, read a bunch of stuff, watched some u tube, checked alternator for A/C noise (less than .01), looked at batteries (looked OK), didn't go away for about a week. Finally I removed each battery cable one at a time cleaned reinstalled, cleaned all the grounds i could reach in engine compartment. Been a week, haven't had a problem since. Just proved to me that connections can look perfect and still not be. Never thought that a electrical system could be so sensitive to a grounding. Just had to fix what I had, didn't need to add anything.Thank you all for your contributions to this thread, especially Mike Nelson aka Mopar1973Man:burnout2:

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I have been fighting this problem with torque converter lock/unlock for at long time. I did everything I could think of and all I could read online. Foil, rewire/ wire modifications, battery replace, clean grounds. Long story short, change out the brake light switch. The dealer hooked the truck up to a laptop and drove it while the truck was doing it's thing. The switch was shorting out sometimes and that was causing the transmission to unlock/ lock. I tell everyone to change this $20.00 switch first before jumping through all the hoops I did

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  • 2 weeks later...

I have been fighting this problem with torque converter lock/unlock for at long time. I did everything I could think of and all I could read online. Foil, rewire/ wire modifications, battery replace, clean grounds. Long story short, change out the brake light switch. The dealer hooked the truck up to a laptop and drove it while the truck was doing it's thing. The switch was shorting out sometimes and that was causing the transmission to unlock/ lock. I tell everyone to change this $20.00 switch first before jumping through all the hoops I did

I have been fighting this for almost a year now. Tried everything posted so far and decided to switch out the brake switch. Just drove 4 hrs and it has not done it once, BUT now my stupid brake light is on! This truck is going to put me in the grave early.
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  • Owner

I have been fighting this for almost a year now. Tried everything posted so far and decided to switch out the brake switch. Just drove 4 hrs and it has not done it once, BUT now my stupid brake light is on! This truck is going to put me in the grave early.

 

Need to adjust the switch when you install it for proper position.

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Need to adjust the switch when you install it for proper position.

Mopar, thank you for your reply! I followed the directions and flipped the black switch after the install like the directions said. But I do not understand how to adjust it further. The directions say nothing about that. Am I missing something?

Edited by rjakin
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I have been fighting this for almost a year now. Tried everything posted so far and decided to switch out the brake switch. Just drove 4 hrs and it has not done it once, BUT now my stupid brake light is on! This truck is going to put me in the grave early.

I have learned that our trucks don't really play well with aftermarket brake light switchs. I am going to be on my fourth one soon as the weather warms some.

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I have been fighting this problem with torque converter lock/unlock for at long time. I did everything I could think of and all I could read online. Foil, rewire/ wire modifications, battery replace, clean grounds. Long story short, change out the brake light switch. The dealer hooked the truck up to a laptop and drove it while the truck was doing it's thing. The switch was shorting out sometimes and that was causing the transmission to unlock/ lock. I tell everyone to change this $20.00 switch first before jumping through all the hoops I did

 

Just called my dealer and they told me their computers can only narrow down the location of the problem, not pin-point it. Said it was going to be a minimum of $70.00 just to start, but then it would be 105 an hour until they found the problem. He said multiple times that the computer systems they have will only give a general idea of where the issue is. I spent about an hour with a cheap multi-meter and narrowed mine down. Reset the APPS sensor and added the BDS wire thing and have not had a problem since. 

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I have an update on my converter lock/unlock problem.  I thought I had fixed it once by adding a ground wire on the alternator, and maybe that did help, but I also cleaned and re-did the battery terminals at that time. 

 

I've now fixed it 3 or 4 times by tightening or cleaning the battery terminals.  Last time, I did nothing except tighten the nuts on the terminal about a quarter of a turn each.

 

Not saying that's the problem on everyone's truck, of course, but on mine, it's working.

 

So the obvious thing to research now, for me, is better battery terminals.

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  • 2 weeks later...

Maybe i could get some help on this. I was having a problem with the torque converter lock/unlock so i replaced the alternator and both battery's since the battery's were getting old and  the problem is gone. i drove it for a day then check engine light came on. i hooked up to it and it saying code P0720 output speed sensor.I was have intermittent issues before this for about a year with the abs light and brake light coming on and off and it has come on twice in the last day now. could this be the PCM going or gone. Any advise would be great. 

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I have gone through all the tips & tricks, tin foil, rewiring, noise & electrical filters, new Bosch alt., none worked, until I tried this.

The ground wire going under the alt. to the passenger side battery connector ground is the bugger your looking for. Disconnect it & follow it back to the drivers side, (by the injection pump), mine has 5 other wires connected to it. Take the main ground wire & run it over to the drivers side battery & then over top of the radiator to the passenger side battery & ground it directly to the battery ground. I used 10 gauge wire & put it in wire casing to make it look pretty & then a ground from battery to the said connector where you disconnected it from.

No more lock/unlock. I went as far as removing all the other magic tricks & put everything back the way it was from the factory. 

I couldn't be happier.   

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My question is why did the truck run 10+ years without these mods but now requires this to work?

 

In my mind something has failed. I don't think wiring mods is the right answer to the issue. (Personal opinion)

Is it possible that some connection in the original ground wire(s) was bad, and that when the ground wires are all re-done and re-routed, it of course got fixed?  And maybe the re-routing actually isn't what solved the problem?

 

I was pretty sure that adding a ground wire to my alternator fixed mine, but I later realized that I had also cleaned and reworked all my battery terminals at the same time.  Since then I've fixed it several times by retightening them.

 

And if anyone has a good battery terminal system worked out, or even a thread where that is discussed and argued about, I'd like to know about it.  I have my solutions, but am open to better ones.  Not happy that I have to tighten mine every couple of months.

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  • Owner

I think the biggest problem is people allow the main battery cables rot internally and start to create these issues. I'm one of the very few people that have factory cable in excellent condition on both trucks. Even my 1996 Dodge Ram 1500 (46RE Trans) should have this lock and unlock issues. Nope... Not happening here.

 

I check the alternator output during my month inspections and re-oil the cables every oil change or inspection which ever occurs first. Like today I gotta pull the 96 down to the shop and check brakes and axles over mostly but while I'm got it in the shop might as well do the full inspection.

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Mike/guys

When taking out the 140A fuse ....... you mentioned removing the blue field wire.

I assume you mean the blue and green loomed wire that goes into back of alternator as a sensor/power feed .....

 

Measured my AC current and its like 0.02 V as var as I can tell ... so dont think an alternator issue but I have a cheap multimeter so want to be sure ... thx

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Mike/guys

When taking out the 140A fuse ....... you mentioned removing the blue field wire.

I assume you mean the blue and green loomed wire that goes into back of alternator as a sensor/power feed .....

 

Measured my AC current and its like 0.02 V as var as I can tell ... so dont think an alternator issue but I have a cheap multimeter so want to be sure ... thx

 

Ok..

 

One method is pulling the blue & wire plug and the alternator fuse and going for a ride. If the problems stop then the alternator is the issue.

 

Another method is to leave everything hooked up and have the truck fully warmed up and idling and measure the output voltage AC at the alternator BATT terminal on the alternator and the battery NEG. If the AC voltage is below 0.1 Volts AC then your fine.

 

The best method is this. Being you can see for sure how much noise is created.

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  • 2 weeks later...

Wondering if I'm having the same problem so before I spend my hard earned tax money on some tranny parts I would like some advice. I have an 01 Cummins 2500 4wd auto tranny with an edge jwa set to 3 to compensate for my 6" lift and 315/75/16's. I'm having the ever so common 40-50mph lock/unlock issue as well as slippage in the 1st and 2nd gear range. Truck has 125k miles and stock tranny. I don't race/drag/plow/ or pull anything really just a typical DD. Could my slippage issues be the result of these problems mentioned above or is it in fact my stock tranny??? Don't want to order parts and spend the money if u guys don't think its necessary....

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