Changing batteries

[heavyduty]

Just put a set of new batteries in my Volvo. Took pictures before stareted was very careful to get everything back like it was. When I started it check engine light is on and part of my Gage cluster doesn't work and shoes ecm needs maintenance. Has anyone run in to this. It was fine before I changed batteries

[spindrift]

Make sure all studs are well cleaned before attaching cable ends and make sure cable ends are tight.

[RandyA]

I keep an assortment of colored zip ties.  When I changed batteries I put a red tie on all positive cables and another color on negative.  I then counted the number of cables/wires to each battery buss bar and wrote the count on a pad as I am prone to forget.  After I thought I had everything back together correctly I discovered I was one cable short on the positive buss.  I started looking for it and discovered It had fallen down the back and was hiding next to an air tank.  You might want to look for a "lost" wire or cable.

[beemergary]

Maybe a good idea to do some back tracking some cables. On my old Pete ther all black. Can run 4 but only 3 batteries. A conduity tester can be handy when you lose track of a wire.

[Big5er]

Any way you might have a bad connector on one of those smaller wires? Also check the inline fuses on the little wires too. Those little wires go to the ECM if I am correct.

What year model Volvo?

[dennisvr]

I second what Randy said.  I've replaced many batteries and have missed a few wires now and then.  Count the wires to each terminal from the pictures you took.  Good luck.

[DesertMiner]

Fuses, fuses, fuses, just like Big5er mentioned!

[RandyA]

OK, stop and think about it for a few minutes.  If I understand correctly everything worked fine before you changed batteries - right?  So, what did you do changing batteries that could now be different?  Fuses are there to protect a circuit or device and sometimes they do fatigue over time and blow without a fault in the circuit.  But, in your case, it is unlikely that you would simply blow a fuse since the current has to come from the other side of the fuse that melts it.  Unless...... and this is the bad part........ unless you got a set of wires on backward (reverse polarity) or there is a ground loop through another circuit or device that current followed before you attached its dedicated ground wire (less probable but it happens).   In any event, if you do find a blown fuse know that this is not normal when a battery swap is made unless something is hooked up wrong.  If you find a blown fuse, don't just pop in another one until you find out what created the increase in current that made it blow to start with. Even the short duration of time it takes to blow a fuse when there is an overcurrent fault can damage sensitive components on a circuit board.  Repeatedly replacing and blowing fuses without first finding the fault can further damage the circuit.  As for the "smaller" wire lugs not making a good electrical connection the problem often found there is not where the lug fastens to the battery but where the wire crimps onto the lug.  Oxidation and corrosion, especially at "on battery" connections can form at the wire to lug crimp that insulates the connection or even eats the wire up so there is no connection.  Simple movement when changing out a battery can be the "straw that broke the camels back" when this happens.

[HERO Maker]

All great advice, especially Randy's.  Hope you have a chance to read his last one before proceeding.

[Big5er]

8 hours ago, RandyA said:

As for the "smaller" wire lugs not making a good electrical connection the problem often found there is not where the lug fastens to the battery but where the wire crimps onto the lug.  Oxidation and corrosion, especially at "on battery" connections can form at the wire to lug crimp that insulates the connection or even eats the wire up so there is no connection.  Simple movement when changing out a battery can be the "straw that broke the camels back" when this happens.

Yeah, thats what I said....Randy just made it sound more gooder 

[noteven]

What is: a missing or loose ground?

[Lance A Lott]

Most odd electronic problems come from bad ground. This can be caused by corrosion at the terminals, a broken or missing (not put back on) wire and loose conection. The term ground refers to any thing that is connected to the negative terminal of the battery. This would include the frame and most metal in the cab. There are wires going from the frame to the cab to keep from loosing ground with the cab mounting points. Some components have there own dedicated ground wire as they are electronically isalated from the rest of the vehicle.

Of course a sink hole in your back yard could also be missing or loose ground.

8 hours ago, noteven said:

What is: a missing or loose ground?

 

[RandyA]

10 hours ago, noteven said:

What is: a missing or loose ground?

On a Volvo VN series truck you will find the majority of cab ground connections under the hood, on the driver side firewall, directly below the windshield.  Often several lower gauge wires inside the cab are spliced into a single larger gauge wire before they are attached to this ground bus.  If one of the wires in a splice bundle should open for any reason it can be a nightmare trying to find where it is located.  Often it is better to just run a new wire to ground from the component than try to find the open.

Look at a possible ground fault in a DC circuit like this one.

+ ---------^^^^^^^------o---------^^^^^^^^--------- +---------^^^^^^^^^-----------o

The ^^^^ things represent some 12 VDC component.  Horn, dash lights, radio, etc.  The + is the positive side of the battery providing power to the component from the fuse pannel.  The o represents ground going to the firewall bus or the negative side of the battery.  The 1st o is a "common" shared ground for the first and second components like in a splice bundle.  The 2nd + represents a 12 VDC positive connection shared by the 2nd and 3rd components.  The last o is another ground for the 3rd component.  Now, if the ground connection at the 1st o is broken the usual result is the 1st and 2nd  components on either side stop working.  But, depending on the resistance imposed by the components it is possible for unwanted current to flow through the 3rd ^^^ component to its intact ground creating a series circuit for components 1 and 2 with a significant voltage drop.   Either way, the loss of the ground creates a hair pulling and cussing problem.  Since the steel chassis and components are prone to corrosion it not uncommon to lose a ground.   The pre-referenced cab ground bus on the firewall is usually painted and has "acorn" nuts to reduce the possibility of corrosion.  If an in-cab problem appears that you suspect is related to a poor ground the first place to start is with the ground bus on the firewall.  Remove and inspect all connections.  Clean if necessary.  Check continuity and resistance from the bus to the negative side of the batteries.  Resistance should be lower than .05 Ohms.  If higher, run a new 6 AWG cable from the bus to the battery negative - no need to mess with the OEM bus ground.

OK - this is just an EXAMPLE.  It is not meant to describe Heavyduty's problem or question.  It is an attempt to answer your question.  I hope it has helped.

[rickeieio]

4 hours ago, Lance A Lott said:

The term ground refers to any thing that is connected to the negative terminal of the battery.

Usually.  Apparently, you didn't grow up around older vehicles, where positive ground was common. Check this out:  http://www.restore-an-old-car.com/positive-ground-cars.html

My brother-in-law was trying to help out an elderly neighbor with his Farmall Cub.  He put in a new battery and hooked it up.  Every time he turned on the master switch, the motor would turn over.  He asked me what was wrong.  In turn I asked him why the fan was turning the wrong way, and got a blank stare.  The tractor had a generator, which turned backwards when voltage was applied in reverse polarity.

He should have known something was amiss when one cable wouldn't slip on the post, and the other wouldn't close enough to come tight.

[noteven]

Sorry guys I was playing Jeopardy with my suggestion-answer-question- 

and yes the info posted is helpful and will be to future readers...

[spindrift]

6 hours ago, rickeieio said:

Usually.  Apparently, you didn't grow up around older vehicles, where positive ground was common. Check this out:  http://www.restore-an-old-car.com/positive-ground-cars.html

My brother-in-law was trying to help out an elderly neighbor with his Farmall Cub.  He put in a new battery and hooked it up.  Every time he turned on the master switch, the motor would turn over.  He asked me what was wrong.  In turn I asked him why the fan was turning the wrong way, and got a blank stare.  The tractor had a generator, which turned backwards when voltage was applied in reverse polarity.

He should have known something was amiss when one cable wouldn't slip on the post, and the other wouldn't close enough to come tight.

Cat emergency generators are famous (infamous?) for their positive ground.

 

[Lance A Lott]

The first tracter we had when I was maybe 10 was a International Cub, it had a positive ground and was 6 volts. I just didn't want to confuse the issue, as I believe the question was for a negative ground system. It was not a very good system and I had to crank start far more times than it ever started off the battery.

We had a International  riding lawn mower, after i left home of course, that had a generator that was also the starter.

[rickeieio]

13 hours ago, Lance A Lott said:

I just didn't want to confuse the issue, as I believe the question was for a negative ground system.

Ahh..  The positive ground was on my mind because I'd spent a big part of the day riding a '49 Farmall Super A with dirty terminals, right in my line of sight.

So, You ARE old enough to have played with some of the weird stuff.

[RandyA]

On 7/13/2018 at 12:14 PM, rickeieio said:

Ahh..  The positive ground was on my mind because I'd spent a big part of the day riding a '49 Farmall Super A with dirty terminals, right in my line of sight.

So, You ARE old enough to have played with some of the weird stuff.

The anomaly here is one that many of us "old timers" have forgotten - and one of which the "newer timers" often have a mistaken understanding.  In a direct current circuit such as the ones on our vehicles, the directional flow of electrons is from negative to positive, not positive to negative as often thought.  Thus, having the positive post of a battery tied to a vehicle frame made perfect sense to electrical circuit designers of the time.  I'll now unplug my electrical trivia channel and return to the original topic. 😖

[rickeieio]

Sooo, is there any reason one way is superior to the other?  The Brits held on to "P" ground for a long time.

Have we drifted off topic enough?

[heavyduty]

All. After 4 days of checking fuses and cleaning every terminal and ground and pulling out what little hair I have left finally narrowed it down to battery voltage. You would think 4 new batteries would have sufficient charge, wrong. They would start the truck but would throw every fault you could think of. Put a slow overnight charge on them and all my problems went away. Just thought I would throw this out there in case anyone else ran in to it. Thanks for all your comments

[DesertMiner]

Thanks for the info. Don’t be too hard on yourself.  You are not the first one to fall under the misconception about “new” batteries being “charged”. The fact is lots of folks may forget to factor in how long those batteries have been sitting before purchase.  Probably the best idea with new batteries is to put a good charge on them before installing them. Good news is you now have a good working knowledge of your battery system and associate components and all of the connections are now clean and tight. 

[noteven]

Aha! So the Cummins is not the only electron powered diesel that is fussy about system voltage at startup attempt...

Dont know if I’ve ever mentioned starting battery disconnection as A Good Thing on a gadget laden parked rv toter... 

but I know rickeieio has 

 

[rickeieio]

1 hour ago, noteven said:

but I know rickeieio has 

Found out the hard way.  That said, of late, I've been leaving everything hooked up if I know I'll be starting the truck in a month or less.  If I had a disconnect, I'd do it for shorter times as well.

I really need a solar charger for the truck and the 5er.

[RandyA]

23 hours ago, heavyduty said:

All. After 4 days of checking fuses and cleaning every terminal and ground and pulling out what little hair I have left finally narrowed it down to battery voltage. You would think 4 new batteries would have sufficient charge, wrong. They would start the truck but would throw every fault you could think of. Put a slow overnight charge on them and all my problems went away. Just thought I would throw this out there in case anyone else ran in to it. Thanks for all your comments

It is unusual to find batteries discharged to the point that instrumentation would not work but are capable of starting the truck.  But, if it resolved your problem I certainly would not argue with you about your success.  What I can tell you as a possibility is Volvo's effort to get away from analog switches and regulator circuits in favor of encoded digital signals on common bus lines.  Examples we have encountered are the power window controls that rely on the lighting control module to transcribe information, the heater controls, four-way flasher button and a proliferation of other devices embedded under the dash.  Unfortunately, the manuals containing schematics give nothing to show what components are potted inside the various control modules - only external connections.  Generally speaking, these modules have an internal gate of sorts to protect them from both over and under voltages.  It could be that such a circuit design was saying. "10.5 volts?  No way I'm letting that guy in.  He is not strong enough to fire the base of an NPN transistor so I will work!"......or something like that.  Electronics can be a mystery if one does not have the complete circuit and values to study.  Sort of like a woman entering a plastic surgeon's office looking wrinkled and harried only to come out the other door a little later with a youthful face reminiscent of a 16-year-old.  What goes on inside stays inside. 😄  ........ and rickeieio, seeing how those guys still have not learned drive on the right side of the road and put a steering wheel where our cars carry passengers I am not surprised some of them still have a positive ground. It is like this:  which VCR format was better, Beta or VHS?  Well, Beta was.  But VHS became the standard.  The best doesn't always win! 😕