2016 Peterbilt 587 Electrical problems

[Alexp86]

I'm having electrical issues with my truck it started right after I purchased it.
I was going down hill on my first trip and the rear axle temp gauge started going crazy, it went all the way to max and back to 0.
So I called the dealer they sent it to a shop that kept my truck over a month claiming they were waiting on parts for the sensor and a few other things including both door locks.
After that I still kept having the same issue I would contact the shop and they would say it's just a defective sensor for me to unplug it or bring it back to them and it would take another 3 weeks or more.... so I decided to just unplug it.
After I'd say a month the abs light started going on going up hill sometimes on a curve, while hooked to traile it would make the trailer lights blink like it was failing but it only does that for a few mins then it goes on steady, abs light also goes on when im bobtail.
About to weeks ago I get to my truck after being home for 8 days and the batteries are dead I assumed I had bad batteries so I went and purchased 4 batteries and replaced it, but then idk if it's just a coincidence or not but when I have the truck off the starter interrupt relay clicks every 2 minutes unless I have the door open.

Another issue I'm having is when I click the snowflake ❄ for cold air the ac fuse pops just this morning I went through 5 fuses trying to diagnose the problem sometimes I can go 2 weeks without it popping and other times it just pops one after the other.
I was told to remove the hvac relay and try it and it looks like it doesn't pop but it could be just one of the times it not popping cause it seems to come and go, I've also disconnected the compressor and it still pops with the compressor disconnected, but thats as far as I've gotten.

I tried taking it to a local shop and they cleaned the axle grounds and starter cables replaced the ground from the starter to the frame and told me I had 25+ohms on the cab and couldn't figure it out charged me 500.00 n said the only way to fix it would be take it to the dealer. I've called numerous shops and they all said take to the dealer we don't have peterbilt wire schematics.... Ive called the dealer and they told me it's going to cost me 2k+ and they're backed up about 3 weeks, so I won't see my truck for over a month...

Does anyone here know what could be the issue or know anyone in jacksonville fl that could help me?

[Alexp86]

I've also replaced all the fuses and relays but that didint help anything.

[Rawze]

If you don't start learning how to work on that kind of stuff for yourself then it is going to eat you alive.

[Rawze]

(02-25-2021 )Alexp86 Wrote:  ... abs light started going on going up hill sometimes on a curve, while hooked to traile it would make the trailer lights blink like it was failing but it only does that for a few mins then it goes on steady, abs light also goes on when im bobtail. ...

- 99% of the time the abs problem you just described is due to severe neglect of the rear axle hub bearings. - Every 250k miles, the rear axle bearings need to be re-torqued. If not then they eventually get so loose that they set off ABS alarms when he truck is heavy, or when you turn corners etc. - Also, wheel seals sometimes will fail, inner tire wear on the rear axles sets in, and all sorts of other issues.

When you got the truck .. did you pull all the axles out and re-torque the hub bearings? -- I am thinking you did not.

If that was not done, then nothing else has likely been done either. Sounds like a severely neglected truck to me.


Matter of fact, your initial post heavily implies that you likely did nothing much to the truck at all after its purchase, except to run off to every shop you could find every time it hiccuped so far. This is going to put you out of business real fast.


used trucks = fixing all the neglect from the last owner once you purchase it. This should be done BEFORE you put it back on the roads. Used trucks do not get sold ready for hauling freight right out of the gate, and if you expect as much, then it seems you are learning that lesson the hard way. - Such is trucking.

Also, running off to shops repeatedly for this kind of minor to medium stuffs is also the wrong thing to be doing if you want to actually make a profit. - Invest in a volt meter, learn how to use it, buy some wrenches and start going thru the truck, do all the neglected maintenance, etc. and fix on it. That is how owner-ops make their money any more. By becoming as self-reliant as possible. Otherwise your just going to continue to sit around all the time while truck payments pile up and no one giving a damn about you or your truck outside of putting the fire(the mediate complaint only) out while all the trees in the rest of the forest burn away.

[Alexp86]

(02-25-2021 )Rawze Wrote:  If you don't start learning how to work on that kind of stuff for yourself then it is going to eat you alive.

I hear you, I've been trying, but this electrical shi#t is kicking my ass I've watched countless videos on diagnosing electrical issues find shorts etc.

[Rawze]

(02-25-2021 )Alexp86 Wrote:  

(02-25-2021 )Rawze Wrote:  If you don't start learning how to work on that kind of stuff for yourself then it is going to eat you alive.

I hear you, I've been trying, but this electrical shi#t is kicking my ass I've watched countless videos on diagnosing electrical issues find shorts etc.

Maybe u get lucky and someone PM's u the wiring diagrams. They are likely on the internet in many places.

[Alexp86]

(02-25-2021 )Rawze Wrote:  

(02-25-2021 )Alexp86 Wrote:  ... abs light started going on going up hill sometimes on a curve, while hooked to traile it would make the trailer lights blink like it was failing but it only does that for a few mins then it goes on steady, abs light also goes on when im bobtail. ...

- 99% of the time the abs problem you just described is due to severe neglect of the rear axle hub bearings. - Every 250k miles, the rear axle bearings need to be re-torqued. If not then they eventually get so loose that they set off ABS alarms when he truck is heavy, or when you turn corners etc. - Also, wheel seals sometimes will fail, inner tire wear on the rear axles sets in, and all sorts of other issues.

When you got the truck .. did you pull all the axles out and re-torque the hub bearings? -- I am thinking you did not.

If that was not done, then nothing else has likely been done either. Sounds like a severely neglected truck to me.


Matter of fact, your initial post heavily implies that you likely did nothing much to the truck at all after its purchase, except to run off to every shop you could find every time it hiccuped so far. This is going to put you out of business real fast.


used trucks = fixing all the neglect from the last owner once you purchase it. This should be done BEFORE you put it back on the roads. Used trucks do not get sold ready for hauling freight right out of the gate, and if you expect as much, then it seems you are learning that lesson the hard way. - Such is trucking.

Also, running off to shops repeatedly for this kind of minor to medium stuffs is also the wrong thing to be doing if you want to actually make a profit. - Invest in a volt meter, learn how to use it, buy some wrenches and start going thru the truck, do all the neglected maintenance, etc. and fix on it. That is how owner-ops make their money any more. By becoming as self-reliant as possible. Otherwise your just going to continue to sit around all the time while truck payments pile up and no one giving a damn about you or your truck outside of putting the fire(the mediate complaint only) out while all the trees in the rest of the forest burn away.

I did not pull the rear axle and retorque or any of that... When I purchased this truck I did take it to a mechanic had them hookup the computer and check the engine transmission etc and I used everything they told me to get the dealer to do/fix before I signed the contract... I didint just get it and start working..
this post was about electrical issues not about everything I did since/before purchasing the truck.

But here are a few things:
The engine needed a new intake manifold the dealer paid for, also needed the a/c to be fixed.

The rear axle had a leak before I even drove it off the lot so they had me take it to a shop near by for them to fix and the way the guy put it is he removed the rear pig resealed the pig and and said the rear axle was in great shape because I asked if it needed to be replaced due to the leak and I didint know how long it had been leaking for.

I had the leaf springs replaced all the bushings that looked bad replaced
Countless air leaks fixed by the shop under the dealers warranty and some I did myself.
The powersteering gearbox was replaced.
All the breaks replaced
Coolant was flushed
I changed all the filters including the air dryer filter

And so much more that I can't really think of right now being I had a really long day.

I do have alot of tools and have been fixing alot on this truck myself. Ive cleaned all the wires and terminals in the battery compartment put in new batteries, changed the blower resistor, will be changing the wiper motor after I get this electrical issue resolved. Also plan on changing the air dryer unit. I've replaced all the fuses n relays, installed the omnitacs myself instead of paying someone like everyone at my orientation.
I know I have so much to do and learn still, but I'm not afraid to get my hands dirty if I don't think I'll screw it up.

[Alexp86]

(02-25-2021 )Rawze Wrote:  

(02-25-2021 )Alexp86 Wrote:  

(02-25-2021 )Rawze Wrote:  If you don't start learning how to work on that kind of stuff for yourself then it is going to eat you alive.

I hear you, I've been trying, but this electrical shi#t is kicking my ass I've watched countless videos on diagnosing electrical issues find shorts etc.

Maybe u get lucky and someone PM's u the wiring diagrams. They are likely on the internet in many places.

That would be nice, but every shop I've talked to said they can't find or don't have diagrams for this truck so they refuse to even look at it.

[Alexp86]

Still trying to figure out the issue I'm having. I've spent a long time looking through wire cleaning grounds etc...

The biggest issue for me atm is the a/c defroster not working. When I click the snow flake to turn the cold air on or if I put it on defrost its popping the fuse.

I've unplugged the compressor and it still pops when I click that snowflake, so I unplugged the high and low pressure switch and it didint pop. If I plug 1 in it doesnt pop but with both switches plugged in it pops.
Does anyone know what could be causing this? I had a friend tell me it's the computer that will need to be replaced and I'll be looking at 5000+ is this true?