Anyone have the details on replacing the VSM? I have no power locks, no auto-lights, the radio stays on when I open the door, and my key fobs don't work. I know it's back behind the radio and the dealer has to program it -- how much of the dash has to come out? I need a new head unit anyway, so I'm thinking now is a good time for that.

BTW, the AutoZone alt is fluctuating like crazy -- voltage jumps around from 12.5 to 14.5, and who knows if there are spikes. I took it in to them & of course they said it was fine. It has now killed the VSM, so they'll be getting a piece of my mind...

 

I hate to hear about the VSM, Joe. IIRC, Chris (RAMPAGE_F350) has gone through the VSM woes and probably has some excellent insights on it. For that matter, Brandon may well have been in the middle of that with him and could also be another resource for you.

Having just gone through the alternator replacement effort, I can speak to what I've seen with a bad OEM unit, and "still OK OEM unit", and a great-performing upgraded HD 160 amp unit. I can't speak to the VSM issue at all, though.

Bad OEM unit: system voltage (per AE) running down slowly from 11.8 volts to 11.4 volts throughout an afternoon while getting back home to change it. No spikes observed because the alternator simply wasn't putting anything out.

Still OK OEM unit (from my wife's Excursion PSD): Running around for the full day after putting this unit on in place of the dead OEM unit, system voltage (again per AE) continued to climp from 11.1 volts to 13.8 volts. No spikes that day at all, and voltage recovery continued to improve through the day as the abtteries were slowly recharged. The next day, both batteries having received full charge from driving around the day before, again no voltage spikes observed at all. With my stop adn go driving, the starting would pull the voltage down to about 13.1 volts at times, but would smoothly run back up to 13.8-13.9 volts within minutes, and no spikes or wild voltage swings observed at all.

New HD 160 amp alternator with remote bridge rectifier box: Installed on fully charged batteries and on the initial startup, system voltage was hitting 14.4-14.5 volts within 1-2 minutes. Driving around with this new alternator and watching the system voltage on AE while driving, idling, startup, etc., the system voltage has not exhibited any erratic swings or spikes, but has rather shown some small, slow voltage reductions when idling for an extended period (~30 minutes). At every voltage reduction resulting from either starting up or idling for a while, the voltage recovery is quite pleasantly quick (1-2 minutes) and steady with no erratic swings or spikes.

Hope this gives you some helpful info, and that you get the details worked through quickly.

 

Subscribing here for more info.
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What I CAN add to this thread is to stress the importance of installing that booster wire in similar fashion to what I did for my truck.
It makes a huge difference in how stable the charge rate is.
The only time my charge rate drops below 14 is if there is enough load to overcome the alternator (glow plugs on, headlights on, wipers on, AC on, engine rpm at idle.

 

Thanks guys- I'm in FL right now so I need to get this fixed before I head back to TX in a couple weeks. Maybe I'll go ahead and put in the 160A HD alt and be done with it.

I remember you put in a larger gauge wire, Dan. How big did you go?

 

4 gauge Positive and 2 guage ground.

 

Joe, can you put a scope on the alt and look at the signal?

 

While I was not involved in Chris' VSM replacement and reprogram, I can tell you that it would be perfectly O.K. to call him and he could walk you through it. He doesnt check the boards regularly anymore, so a PM would most likely go unanswered. If you cant find his number on the RHN, call me or shoot me a PM and I will give it to you.

Where abouts in FL are you Joe? You just visiting, or are you training?

 

Thanks guys.... I'll be pulling it tonight to see what Autozone says. Just looked at the HD 160 alt and will probably pull the trigger on one later today.

I'm in Ft. Myers after about a week in Tampa. Got some other things going on as well (5 days in the US Virgin Islands....

EDIT: Can't look at it with a scope, Pat. Don't have one with me.

 

Joe, please note that if you order from Quick Start, you will see a 2-day order processing delay before anything gets shipped at all.

 

Pete do you have a link for Quick Start? I want to keep my options open. My alt gave up the ghost in TN while loading up Jodys parts truck. He graciously gave me the one that was removed from it. I believe that my alt took a "shock" from Platinum Petes truck when his truck pulled enough juice from mine to stall it. He had,IMO, a bad plate in his battery that ocassionally would short out, this took out his starter and eventually his alternator and mine too.

 

It's been about 3 years since I had to change out my VSM but as I recall I could get the 3 connectors off the VSM without pulling anything but to unbolt it from the firewall, I ended up pulling the lower center section of the dash to gain access.

I did all of this in hopes of saving a little labor at the dealer but with the 10 minutes it took in the shop bay to re-program the VSM, they still charged me the full hour.

 

This is what i also experienced at my dealer, they told me the charge would be 1 hour to reprogram the VSM and it would only take 20-30 minutes to do that, they said they could install the VSM and reprogram it for the same price, it was a no brainer for me.

Good Luck

P.S. i also run a Quickstart alt, 140 HD internal Rectifier FWIW.

Edit: I bought my VSM from "Parts Guy Ed"

 

Dan,
Are you using the new lead along with the stock cable or as a stand alone?
Sorry for the hyjack!

 

Got my vsm out by taking out the radio and the lower center dash section out. Pretty quick work. You will need a stubby ratchet to get to the right side nut - if I remember right. BTM the VSM is mounted on the firewall right behind and slightly lower then the radio.

I purchased the VSM form Ed for about $120. After getting access to the vsm I let it hang down so that the tech at the dealer had an easy access to it for the swap. Ask Ed for a build sheet for your truck. In my case the tech needed it for programing the new one (the old one was fried). The dealer charged me $145 for reprograming..................

 

Those cables were installed piggyback in addition to the factory wiring harness.
Nothing was removed from the factory wiring harness before I installed those two cables.