Tracking Electrical Problems - a Saga

[Chad Heiser]

LONG POST - Read at your own peril. 

Over the Thanksgiving Holiday, we hooked up the truck and trailer as per usual in order to get ready to head out.  For this trip, I also wanted to bring the Jeep along.  I hadn't done this yet with the new DRV, but everything was wired up in the trailer to be plug and play (partly from the factory and partly from me).  I pulled the Jeep in behind the trailer and hooked everything up.  Before we headed out, I did my light checks. 

Running Lights - Good. 
Brake Lights - Good. 
Left Blinker - Good. 
Right Blinker - FAIL. 

The front and mid blinker on the truck were working, but the rear blinker on the truck, the trailer blinker and the Jeep blinker were all dead.  I disconnected the toad wiring harness and tried without the Jeep connected.  Everything worked as expected.  I reconnected the Jeep and tried again.  Same result, no right blinker from the back of the truck to the back of the Jeep.  There was no way I had time to dig into the issue and there weren't many right turns to be made on the trip (all highway for the length of the trip), so I decided to head out anyway and deal with it later.  All the other lights worked after all.  During our stay at the RV park over the holiday, I did a little more tinkering and as before everything worked until I plugged the Jeep in so I thought for sure the issue was in the Jeep somewhere, but that was as far as I got.  We had a nice time for the holiday and headed home at the end of the weekend.

It was after Christmas before I was able to dig into the problem again, but I finally made some time.  We don't double tow very often and everything worked without the Jeep hooked up, so it was a low priority issue.  When I finally got into it, I started at the Jeep because logically I thought that was where the problem was.  I added a plug and play toad tail light system to the Jeep that activated the factory taillights (that worked fine behind my last 5er by the way) and I figured there must have been a loose connection or bad ground somewhere in the added wiring.  I troubleshot the system from the umbilical cord at the front, through the 6 pin connector and the wiring all the way back to the tail lights.  I couldn't find any issues.  I plugged the Jeep into the truck 7 pin directly and got the same issue I had when the Jeep was behind the trailer.  Everything worked except the right blinker and it still killed the rear blinker on the truck, but not the mid or front blinkers.  I drove the Jeep over to my neighbor's place and plugged it into his pick up.  Low and behold, everything worked as expected - including the right blinker.  Obviously now I know the problem is not in the Jeep, it has to be in the truck.  I gave up for the day and decided to work on it later.

The next weekend (New Years), I had a couple of hours to play around.  I pulled the 7 pin at the rear of the truck and checked the connections there.  By grounding out the right blinker in the 7 pin, I was able to duplicate the symptoms from previously - no rear right blinker, but the mid and front blinkers continued to function.  I didn't have time to do any more, but I did order a new blinker relay just in case.  It was only a couple of bucks on Amazon and if that solved my problem it would definitely save me a lot of trouble shooting time.  My theory was the relay was dying and wasn't pushing enough power out to the back of the truck to power the right blinker with a load on the system.  I have LED lights at the back of the truck and on the trailer and the Jeep has incandescent lights, so this added to my thinking that the additional load of the Jeep incandescent light was overtaxing the relay.

The blinker relay arrived during the week.  When the weekend rolled around, I went down to the shop and crossed my fingers.  I plugged in the new relay and gave it a shot.  Everything worked until I plugged the Jeep in, then dead right blinker again.  Oh well, it was worth a shot.   I put a meter on the right blinker circuit at the rear of the truck and found I was only getting 6 to 7 volts on that circuit.  I know the wiring is a mess under the truck from previous experience and I have been dreading cleaning it up because I know it is going to be a pain to do.  (They wiring is all original to when I purchased the truck.)  I spend the rest of the day and all of the next day under the truck redoing every connection from the 7 pin all the way up to the firewall.  In the process, I also clean up all the wads of wire and air lines under the truck.  It was a long, arduous and dirty job.  I pulled close to 100 feet of excess wires and plugs from under the truck bundled up along the frame rails and cross members.  I have no idea what all the wiring was originally for, but it wasn't connected to anything so it wasn't doing me any good anymore.  I also found a few air lines that just went nowhere and were not capped off.  I removed them as well. 

My truck doesn't have a Jackalopee or a Hoppy or any other type of relay system to properly power the recreational trailer wiring.  Whoever originally did the conversion on my truck cut and spliced wires at the firewall in the engine compartment to make the trailer wiring harness work like a recreational wiring system.  They spliced the trailer wiring into the wiring for the taillights of the truck at the firewall.  It is not the way I would have done it, but it has worked for who knows how many years.  I did redo all of these splices with better connectors and heat shrink as well.  After all this, I figure things have to work now.  Everything is connected and grounded properly.  All the connections are new and using high quality connectors.  I plug the Jeep in and cross my fingers.  I hit the right blinker and ...... Nothing.  It's still dead at the back of the truck and the Jeep, but working at the mid ship and front blinkers.  I test the voltage of the right blinker circuit at the back of the truck and at the firewall and am still only getting 6 - 7 volts.  After two full days of troubleshooting, redoing connections and pulling wire I am, to say the least, a bit frustrated.  

I give up and go back to work for the week.  The next weekend rolls around and I start on the interior of the truck.  I trace the wiring through the firewall and find it on the other side after pulling a bunch of lower dash panels.  I test the voltage on the inside of the firewall and still only get 6-7 volts.  This eliminates the firewall connector as the weak point, which was good because it has 50+ individual wires going through it and I did not want to think about pulling it apart and tinkering with it.  I trace the blinker wire all through the dash (it goes through the firewall in the passenger foot well) over to the driver side to the steering column and the blinker switch and then back to the passenger side where the fuse panel is located behind the glove box.  I find I have low voltage from the firewall all the way to the blinker switch on the steering column, but good voltage on the other side of the blinker switch all the way to the fuse panel.  The problem has to be in the blinker switch.  I quit for the day and start hunting for a new blinker switch on the internet.  I find the assembly and order it.

The blinker switch assembly arrives during the week.  Saturday rolls around and I take it down to the shop and go to install it.  I pull the old one and all the electrical connections line up, but the mounting bracket is different.    I examine the two parts and determine I can remove the incorrect mounting bracket from the new part and transfer the correct mounting bracket from the old part.  Three screws on each part and the swap is done.  I mount the new switch in the truck and reconnect the wiring.  I cross my fingers and test all the blinker operations without the Jeep connected.  Everything works.  I plug the Jeep in and test again.  Everything WORKS!    I button everything up and thank my lucky stars I finally found the problem. 

I knew I would eventually solve my problem because I am pretty good with electrical systems and I am always systematic when checking electrical systems.  Always start at one end of the system and systematically work your way to the other end until you find the problem. It always works.  

In this case I was just a little bit unlucky and STARTED AT THE WRONG END!   

Had I started at the fuse panel in the truck and worked my way back, I would have never gotten out of the cab of the truck.  I would have found the problem in a couple of hours, ordered the new blinker assembly and been done.  However, I would still have a bunch of questionable connections running to the back of the truck and a BUNCH of useless wire and air hose stuffed up along the frame rails doing nothing for me.  I guess it all worked out the way it needed to.  

I just thought I would share my trials and tribulations on this particular project.  Hopefully it was entertaining (and maybe a little educational) to some of you.

[Alie&Jim's Carrilite]

This sounds all too familiar.  I removed 3 spliced and diced 7-way harnesses from the truck when I put the Jackee in.  I was amazed that anything worked at all.

[HERO Maker]

Chad, all I can say is WOW!  If I ever have a problem (electrical wise), I'm headed in your direction!

Great job tracking it down.

[Chad Heiser]

I left a couple of steps in the process out.  The story was long enough without getting into too much detail.  I was taking my time with the troubleshooting and R&R of all the connections.  I could have done it faster, but wasn’t in any particular hurry.  

Crawling around under the truck is always an adventure.  By the end of the day I am always covered in dirt and grit from head to toe and I’m not allowed to wear those clothes back into the house when I’m done.  Think coal miner coming out of the mine at the end of the day.  It takes a while to get cleaned up.  It’s amazing where dirt and grit can lodge itself under a truck and then come cascading down on you when you disturb it.  And this is on a relatively clean southern truck that never saw snow and salt.

At least with the shop, I’m now working on a nice concrete floor instead of the gravel driveway I used to have to crawl around on.  I look at these adventures as learning experiences.  I’m now much more familiar with the complete electrical system in the truck and how it is layed out.  I traced and followed a lot of wires during this process.

 

[Chad Heiser]

2 hours ago, Alie&Jim's Carrilite said:

This sounds all too familiar.  I removed 3 spliced and diced 7-way harnesses from the truck when I put the Jackee in.  I was amazed that anything worked at all.

At some point in the future I’d like to put the original wires back together at the firewall and put a jackalopee in down stream to clean things up even further, but everything works now so it isn’t high on my priority list.

1 hour ago, HERO Maker said:

Chad, all I can say is WOW!  If I ever have a problem (electrical wise), I'm headed in your direction!

Great job tracking it down.

My hourly rate is probably cheaper than most shops.

[mr. cob]

Howdy Chad,

Well done Sir, well done indeed.  I simply don't have the knowledge or patience to do such work, I am sure had I touched such a job the sacred smoke would have been rolling out of everything from the dash board of the truck to the tail lights of the Jeep.

Dave

[Brad & Jacolyn]

9 hours ago, Chad Heiser said:

 

Crawling around under the truck is always an adventure.  By the end of the day I am always covered in dirt and grit from head to toe and I’m not allowed to wear those clothes back into the house when I’m done.  

 

 

I understand the part about not being allowed in the house. I was told that once and then stripped naked right in the driveway. I was allowed as far as the garage area after that with the dirty clothes on.

Brad

[dennisvr]

Sounds like an adventure for sure.  I'm pretty good at electrical but, I hate to work behind the dash.  Never enough room and it always seems like I start at the wrong end and have to take every panel off the dash before I get to the problem.
Like I tell everyone "Why is the problem at the last place you look"  
Chad thanks for the reminder.  When I extended my frame I lost the right turn signal on the rear of my truck.  Like yours the front and mid worked and I was leaving for Arizona and the trailer was find so I headed out.  Well now that I'm setting in I can dig into it.

[lockmup68]

I think we should have a "how to use a mulitmeter" workshop at the ECR and National Rallies. Still cleaning up the bird's nests in my rig. I did get the jackalopee in and working and all new wires front to back, but I mostly left all the crap zip tied to the framerails as I didn't have time to track it down front to back. Let's just say there are LOTS of zip ties under there.

[Chad Heiser]

2 minutes ago, lockmup68 said:

I think we should have a "how to use a mulitmeter" workshop at the ECR and National Rallies. Still cleaning up the bird's nests in my rig. I did get the jackalopee in and working and all new wires front to back, but I mostly left all the crap zip tied to the framerails as I didn't have time to track it down front to back. Let's just say there are LOTS of zip ties under there.

My frame rails are a lot cleaner with a lot less zip ties now.

[Chad Heiser]

2 hours ago, Brad & Jacolyn said:

I understand the part about not being allowed in the house. I was told that once and then stripped naked right in the driveway. I was allowed as far as the garage area after that with the dirty clothes on.

Brad

I'm at least allowed into the garage, but the clothes get dropped on the garage entry steps.  Then they stay there until wash day.

[noteven]

 Chad is The Electron Whisperer 

[oldbutspry]

Thanks for sharing!  Sounds like an adventure.  I like doing electrical work but not when it involves taking the dash apart.

[Chad Heiser]

36 minutes ago, oldbutspry said:

Thanks for sharing!  Sounds like an adventure.  I like doing electrical work but not when it involves taking the dash apart.

The dash on my T2000 is pretty easy to take apart.  I completely rebuilt it to repair a bunch of broken fasteners after I bought the truck.  It has been apart multiple times since then as well to run new wires and camera connections and monitors and etc.  I've never pulled a Volvo dash apart, but from what I have heard it takes quite a bit more effort than mine.

[oldbutspry]

38 minutes ago, Chad Heiser said:

The dash on my T2000 is pretty easy to take apart.  I completely rebuilt it to repair a bunch of broken fasteners after I bought the truck.  It has been apart multiple times since then as well to run new wires and camera connections and monitors and etc.  I've never pulled a Volvo dash apart, but from what I have heard it takes quite a bit more effort than mine.

It's always nice when the people designing a vehicle bother to make it easy to repair/maintain!

Your comment about "camera connections and monitors and etc" gives me an idea for a new thread.

[Alie&Jim's Carrilite]

The Gen 1 dashes are easy.  2 screws for the gauge display, 2 for the upper drink holder and that gives you access to the upper dash.  The bottom panels are 8-10 screws and their out.  Wrestling the panels around the floor mat takes longer than unscrewing them.

For the most part, all the HDT brands are easy to work on behind the dash compared to their LGT counterparts.

[Scrap]

I swear this year is the death of the 90's mechanical turnstalk.  I've done three with different turn signal weirdnesses since this summer.  One of our Challenger tractors, our T8, and my VW all ate em.  I'm sure a guy can take em apart and clean and re-lube em but I pretty much run out of patience at that point.  The VW I put the column back together with a new turn stalk, new wiper stalk, new steering wheel, and a new shifter knob.  Feels like I got a new car! 

[Pete Kildow]

Wish we lived closer. Would well be worth a dozen BBQ rib and Brisket dinners. My Kenworth has a issue. The kind I hate, the kind that is causing a short. A short that will drain the batters in 12 hours. Then charge everything up, and may not do it for a week or 2 weeks. Then next time do it again. One of the main hot cables will spark when it touches the batter.

Tested every breaker and fuse. Pulled some hair out of my head. A few bad words. And 9 weeks later. Still doing the same thing..

Glad you found your issue. 

Pete

[accumack]

I know this is not the same thing but I would have the alternator checked out . I had a Chevy S-10 pickup that every few weeks would end up with a dead battery. It would go weeks at a time no problems. I had a good starter /alternator rebuilding place nearby and took my alternator to be checked they found a problem that if it stopped at a certain point it would drain a battery. I hope this helps.

[Ronbo]

Pete, open one of the storage doors and look through under the bunk to see if the light on the other side is on. The close that door and check the other side. I had a light staying on and when I removed the bulb no more problem. 

[HERO Maker]

On 1/23/2018 at 10:36 AM, lockmup68 said:

I think we should have a "how to use a mulitmeter" workshop at the ECR and National Rallies. Still cleaning up the bird's nests in my rig.

There are lots of good videos out there explaining how to use the multimeter.  And I don't like electric!!!  But not really too hard.

But Chad is the man!