Troubleshooting electrical issues

[kendelrio]

All-
I work offshore with robots and one of the things I teach is electrical troubleshooting.

With my new guys I've noticed a lot of times they tend to either overthink the issue or are so intimidated by the system their brain freezes up.

My advice to them (and it helps on MVs too) is to not look at the entire machine. That tends to be overwhelming. Focus in the trouble area and:

1. Find the commonalities. If more than one component isn't working or is malfunctioning, trace the system to the part in common. For instance: if **none** of your lights are working, odds are the lights aren't bad, you would follow the "signal source" and check the switch (is it working) the batteries (are they dead) etc, which leads to my next piece of advice.

2. Work "E" to "H". Most of my guys think that means Electrical to Hydraulic, when in reality I mean work "Easy" to "Hard". Why jump into changing a wiring harness when the issue may be something as simple as a corroded connector?

Some people tend to replace things until the problem goes away. I don't have that kind of budget, and I also like to know WHY a component failed in addition to what component failed. If its design, I try to find a better design. If it's maintenance or use related, I'll try to figure out the proper maintance or procedure for use.

1. Commonalities
2. E to H

Best of luck and may you never have to troubleshoot!

 

[Mullaney]

All-
I work offshore with robots and one of the things I teach is electrical troubleshooting.

With my new guys I've noticed a lot of times they tend to either overthink the issue or are so intimidated by the system their brain freezes up.

My advice to them (and it helps on MVs too) is to not look at the entire machine. That tends to be overwhelming. Focus in the trouble area and:

1. Find the commonalities. If more than one component isn't working or is malfunctioning, trace the system to the part in common. For instance: if **none** of your lights are working, odds are the lights aren't bad, you would follow the "signal source" and check the switch (is it working) the batteries (are they dead) etc, which leads to my next piece of advice.

2. Work "E" to "H". Most of my guys think that means Electrical to Hydraulic, when in reality I mean work "Easy" to "Hard". Why jump into changing a wiring harness when the issue may be something as simple as a corroded connector?

Some people tend to replace things until the problem goes away. I don't have that kind of budget, and I also like to know WHY a component failed in addition to what component failed. If its design, I try to find a better design. If it's maintenance or use related, I'll try to figure out the proper maintance or procedure for use.

1. Commonalities
2. E to H

Best of luck and may you never have to troubleshoot!

Sounds to me like you also know about the KISS Keep It Simple Stupid moniker...
It is strange how people can freeze up on the size of a problem.

NICE information to share with the group kendelrio !

Tim

 

[NDT]

Good advice. Had to chuckle a little about your example of "all lights not working", with our trucks it happens a lot that the alternator voltage regulator fails with very high voltage and blows out all light bulbs leading to very confused techs.

 

[antennaclimber]

Great information Ken,

Trying to find people that can take a logical step by step evaluation on troubleshooting is difficult. The process of elimination seems to be a lost art. More times than not, it is something simple. ON/OFF switches seem to really confuse some people.

Many people are relying on a computer to tell them whats wrong. My friend has car dealers asking him to come and fix engines in new cars that are not running right (missing). "The computer says it's fine, no error codes." So he has to teach the service techs on how to diagnose it the old school way.

It's Rocket Surgery to them, basics to us Old Guys.

 

[tobyS]

Back of a tail light. Notice bare wire where it comes out of the box, sandwiched between box and steel back plate.

 

[kendelrio]

Back of a tail light. Notice bare wire where it comes out of the box, sandwiched between box and steel back plate.

I do notice it!

 

[dmetalmiki]

Chrysler jeep...Not running on gas. (GAS not gas!).

four chaps debating the fault.

Off came the pipes..Out came the gas tank (1/2 way anyway then got stuck.)

Off came the pump, then anything and everything meddled with,

By this time I'm on my second bag of crisps...

Says I, "Change the filters", ( three ).

Ran like a gem!. Nay, two gems!.

 

[tobyS]

While fixing the light above I found something that I didn't know. Both of the mounting bolts are used for ground. One is the stop run lights and the other is the blackout. I understand the power wire being separate but why the ground? Of course one needs a quality connection of bolt to frame with the left bolt for stop and running lights to work.

 

[kendelrio]

While fixing the light above I found something that I didn't know. Both of the mounting bolts are used for ground. One is the stop run lights and the other is the blackout. I understand the power wire being separate but why the ground? Of course one needs a quality connection of bolt to frame with the left bolt for stop and running lights to work.

Off the top of my head, being as they are two different circuits, they would have separate grounds.

 

[Mullaney]

Off the top of my head, being as they are two different circuits, they would have separate grounds.

.
As odd as it sounds - logic is that "ground is ground". Apparently the military in a lot of cases have power and ground as separate "home runs" in a lot of cases. The LMTV/MTV is a good case for that argument.

(PRO TIP WARNING: Remove The Battery Cables First!)

If you sit in the passenger seat, pop off the cover for the fuse panel and unscrew the mounting screws that hold that board in place. Gently tip the board back toward you and you will see a buss bar with spade connectors that are ground connections. (all small white wires) Ground for the lights, gauges, and a host of other things are grounded that way. A lot of those wires go to the under side of the board to provide ground at the fuse level.

---

Hope everybody got a chuckle about the "Pro Tip" Warning. If that board gets shorted out to ground it will make you unhappy and pretty miserable. Hopefully that was a fun way to let everybody have a chance to see potential for a problem... (Not sure that I qualify as a "Pro" either, but it made a better story!)

A smoking truck is no joke!

 

[JD4044M]

.
As odd as it sounds - logic is that "ground is ground". Apparently the military in a lot of cases have power and ground as separate "home runs" in a lot of cases. The LMTV/MTV is a good case for that argument.

(PRO TIP WARNING: Remove The Battery Cables First!)

If you sit in the passenger seat, pop off the cover for the fuse panel and unscrew the mounting screws that hold that board in place. Gently tip the board back toward you and you will see a buss bar with spade connectors that are ground connections. (all small white wires) Ground for the lights, gauges, and a host of other things are grounded that way. A lot of those wires go to the under side of the board to provide ground at the fuse level.

---

Hope everybody got a chuckle about the "Pro Tip" Warning. If that board gets shorted out to ground it will make you unhappy and pretty miserable. Hopefully that was a fun way to let everybody have a chance to see potential for a problem... (Not sure that I qualify as a "Pro" either, but it made a better story!)

A smoking truck is no joke!

Great this is what I was looking for! Now I need to get out and pull the Fuse Panel and take a look. Getting ready to drink my Colon Test stuff so I need to do this soon! I thought it might be under there but was not going to unscrew it till I was sure. Thanks!!

 

[JD4044M]

Wow got Both Head Lights now?! Made a temp ground jumper behind the housing and no lights still? This is after I almost removed the panel and had second thoughts about doing that. Wiring is pretty clean/un touched on the truck and I like that. Then looked for why it did not make it into the housing? It had a good connection on the outside, good one on the inside, dead one on the added Jack! Found it and the wire broke when the insulation was crimped in the add on Jack for the LED's! Had nothing to do with the Trucks wiring. Fun when multiple things happen at once. The Original Head Light had no Low Beam the reason I changed to LED. So that thru me off in the beginning with what could be wrong with nothing that is wrong! Instead it is the new light now having a connection problem. Solved and all is fine. I always did like trouble shooting something I never saw before! My Cat's Help too no mice on my truck or property. They sleep in the heat under it away from the sun.

 

[kendelrio]

Wow got Both Head Lights now?! Made a temp ground jumper behind the housing and no lights still? This is after I almost removed the panel and had second thoughts about doing that. Wiring is pretty clean/un touched on the truck and I like that. Then looked for why it did not make it into the housing? It had a good connection on the outside, good one on the inside, dead one on the added Jack! Found it and the wire broke when the insulation was crimped in the add on Jack for the LED's! Had nothing to do with the Trucks wiring. Fun when multiple things happen at once. The Original Head Light had no Low Beam the reason I changed to LED. So that thru me off in the beginning with what could be wrong with nothing that is wrong! Instead it is the new light now having a connection problem. Solved and all is fine. I always did like trouble shooting something I never saw before! My Cat's Help too no mice on my truck or property. They sleep in the heat under it away from the sun.View attachment 840847View attachment 840848

That's a sexy set of ummm... headlights!