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Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 9822
Experience:  worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling
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Wayne. I hope that I can explain the situation correct so

Customer Question

Hello, Wayne.
I hope that I can explain the situation correct so you understand what is going on with the truck.
05 VNL670 ISX.
I've got weird sound from under the hood, not constant, but intermittent after every truck wash or long time heavy rain. You can compare the sound with belt skipping. At the same times that noise appears the cluster is blinking and batt voltage is dropping to 12.X/11.X and goes back to 14.0 as weird action ends. Have to drive 20/30 miles till everithing goes back to normal.
This may help. Relay F8("Icon crank allow") is related to the problem somehow, because it is vibrating at the same time that weird noise and dashboard lights blinking beginning.
Dont know if its short circuit or starter solenoid going bad, or ... .
No other electrical problems on the truck.
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Wayne replied 1 year ago.

Hi I'm Wayne

I will help you with this

Thank you for requesting me

Yes that is strange

my 1st thought is the alternator or the belt slipping

Reason I say that is voltage drop, and gauges flashing

it is either a poor connection,remove and clean all terminals on alternator

the noise you are hearing is the alt kicking in and out

and the belt slipping

or just replace the alternator

I hope this helped you

Hi if this helped you

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Expert:  Wayne replied 1 year ago.


I am just following up with you

did my answer help you

let me know , Please