2nd Gen Non-Engine/Transmission New Game: Troubleshoot This

[Morphious]

Hello all, got an issue I'm trying to trace down, so I'm going to give a description of all the symtoms I've discovered so far and we will see who can come up with the correct answer to my problem.





Here is what is happening:



the issue started out as a random rare occurance, but has gotten gradually worse to where it is almost all the time now.



the problem is a flicker in the electrical system that affects the dash lights, headlights and will occasionally cause the engine to stumble. This will happen with the headlights on and the headlights off. This will happen with the engine running and the engine off, key on or key off. I just replaced the Alternator, it went out a few weeks ago, but it was doing it before it went out and is still doing it after replacing it, that was the original alternator with about 300k on it.



I have a secondary fuse block on the truck and everything powered off of it works fine, no issues. I don't believe it's the headlight switch as it affects more than just the lights, it's not the alternator or power fluctuations from it or the battery. I'm running a single odessey 2100 cca battery in the truck. It happens when the engine is cold or hot, dry or wet outside, cold or warm outside. I've never replaced a relay on the truck, so they are all original, 10 years old and 300k miles on them.



Does anyone have a wild guess as to what the problem could be? I drive 1200 miles every other weekend in the truck to see my kids and don't want to be stranded during one of those trips.



Morph

 

[Gene Arnold]

Bad ground?

 

[MLee]

One battery, how long has it been in service? have you tried another battery in its place to be sure? How about a corroded battery cable? could be a relay. Bad ground sounds good, as mentioned.

 

[Gene Arnold]

I just read some pertinent ground info on the General Diesel forum. I don't know how to attach the correct info to go there but I copied:

https://www.turbodieselregister.com.../89040-electrical-grounding-finer-points.html

 

[fest3er]

As Gene says, it's most probably a ground. If a connection isn't solid or is aging, it can build up a bit of corrosion, which is electrical resistance; the resistance can vary with the load as the the junction heats up and cools down.

To prove it, connect one jumper cable clamp to the negative post. Connect the other end to various ground points on the truck. If you find a point that makes it stop, you'll've found the bad ground. If using the negative doesn't work, use the positive post, and connect the other end to various B+ sources in the truck. The more proper way to do this is to disconnect the battery and use an ohm meter to measure the resistance across various junctions; if you see more than . 1 ohm or so, you should address the junction before checking any more. Or if you see less than B+ where there should be B+, you should address the problem before moving on.

But, before you do all that, try an easy test: disconnect the intake heaters. The OEM heater relays are known to do strange things (though causing the engine to stumble isn't one of them).

 

[Mikey-KE7LBB]

I haven't paid any attention if the 24v has fuse links or not, but I experienced a similar problem with my 92 and I found a fuse link that was broken inside the shielding, but never got hot enough to burn all the way through. It could also be a ground issue or burned or corroded contact points on main fuse block where power comes in.

 

[ChuckKelly]

i agree with mikey

 

[Morphious]

All main + and - cables were replaced 2 years ago with heavy duty battery cables, all connections crimped and then soldered. The battery is less than a year old (1st had cells go bad), the system is charging and like I said, the items running off of my secondary fuse block have no problems and those items are frame grounded as well. I've checked all wires I could find on it. the terminals are brass screw on lugs with military terminals with all new wires on the truck. I did swap out two relays today and the problem hasn't reoccured again since then, i'm going to drive the truck for a while and see if it reoccurs, if it doesn't, I'm going to go buy some new relays and replace all of them in the main distribution block.



Morph.

 

[KYOUNG]

make sure that the big fuse coming off the alternator is good, check them all with an olm meter and make sure they all read zero.

 

[CYDiesel]

I had the same problem on mine several years ago. I found a loose connection in the distribution box aft of the drivers side battery. Check the main power and ground leads coming into the the box and the high amperage fuse near them for security. I can't remember which of them was loose on mine. I found it because I could see the arcing. My truck is also a '99.

 

[Morphious]

I've already checked all of the connections like that, they were all secure. I'm starting to think that it was a relay that was going faulty, I swapped around 4 relays yesterday afternoon and haven't seen it reoccur again. I drove it about 60 miles last night with the headlights on and never saw it flicker once. I'm hoping that's what it was, I've checked in the cab for shorts, in the engine compartment, etc... over the last few weeks trying to narrow it down. I'll keep updating this as i drive the truck and see if i see it occuring again.



Morph

 

[ToolManTimTaylor]

Check the 10MM nut that hold the MAIN wire connector in the fuse box under the hood. Theese vibrate over time and WILL loosen up. Now do NOT freak out when tightening it as it is a torque limited bolt assy. it will feel as though it is stripped. This is not the case. While "wiggle Pushing" down on the connector keep a tightening tension on the head of the bolt. i am willing to bet it is loose.



Had I found it earlier it would have saved me 135. 00 flatbed tow back home. I have seen it on several trucks thus far and that connection harbors a signal feed to the ECM as well.

 

[Morphious]

Well, it's now tuesday and with driving the truck to and from work and other trips in the truck with the headlights on, I haven't had the flickering occur again, so i'm now going to say that it was one of the two sets of relays I swapped, I know one was the ASD Relay and I'm betting that was the one that was going bad. I'm going to go out and replace all the relays as I get time since they are all 10 years old and have about 300k on them. When one starts to fail, the others can't be far from it as well. I'm going to consider the issue solved unless I have another reoccurance of the problem.





Morph.

 

[MLee]

Good for you Morph. Simple is Priceless. Just nerve racking.

 

[Morphious]

Yeah, talk about nerve racking, driving dark remote rural highways in ne oklahoma with winding curves and your headlights are sitting there flickering like crazy, definately caused a pucker factor.