Jump to content
Sign in to follow this  
jwmcgregor

VECU Help

Recommended Posts

2010 CHU wouldn’t crank to move out of the shop this morning.  Drove in to the shop working fine.  I see we also have failure of tail lights, wipers, PTO, diff lock, air slide, fuel gauge. I think the datalink is not functioning as well as I can’t connect service tool.   The dash powers up and the lightning bolt is illuminated. Fuses are all good.   VECU?  If so...Are they generic so I could swap one from a sister truck?  

Thanks 

Edited by jwmcgregor

Share this post


Link to post
Share on other sites

I moved the VECU from the non working tractor into a sister tractor....The VECU worked fine.  I have no key to the BEC fuse panel.  Was not in the trucks and dealer seems unable to produce one.  I've got 12v on both sides of all the fuses in the panel except two.  Two have no power at either side but the sister trucks are the same way.  Start swapping relays between the tractors?  I downloaded some drawings that Mackpro posted.  From what i can tell the VECU is the only "smart" hardware in the circuits for the functions that are failing.  I can't find information to see if the VECU has power and ground to it.  Power through one of the big relays under the dash or power from a relay on the BEC?   

Share this post


Link to post
Share on other sites

The iginition relay and EMS relay are passing 12 volts through like they are supposed to.  The EMS pre ralay is clicking when the key is turned on.  The only relay that is not actuation as it is on the sister truck is the emergency stop lamp relay.  I see it connected to the tractor stop lps fuse.  That fuse is fine.  

Share this post


Link to post
Share on other sites

Resolved....The Deutch connector at the firewall (MC??) had threads smeared when it was removed.  It did not install together properly as the jack screw did not pull the Deutch connector together all the way.   Repaired with tap and die.  The molded nut in the deutch connector on the firewall side will spin in its molded housing.  Looks like a "be careful spot"

Thanks again Challenger!  

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

Welcome to BMT!

...The world's best antique, classic & modern Mack Truck support forum! Founded in 2000, BigMackTrucks.com is the place to go for everything related to Mack Trucks!

BMT!

BigMackTrucks.com is owned and operated by Watt's Truck Center, New Alexandria, PA. This forum and it's contents are not affiliated with Mack Trucks, Inc. or Volvo Trucks North America.

×