RPM's

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Apr 20, 2008 | 08:09 AM

rungunner

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Joined: Dec 2007

Posts: 88

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From: MI

RPM's

Ok fellas here is something I need to know. 1997 f-350 with a 7.3 diesiel. Driving down the highway at 70 MPH with my foot on the gas or in cruise control if I turn on my right turn signal the motor with speed up slightly and if I turn the signal off it drops. Any ideas other than some kind of short in the signal handle?

Apr 20, 2008 | 09:22 AM

Cuda_jim

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Joined: Oct 2003

Posts: 5,903

Likes: 1

From: MICHIGAN

If you have a trailer brake controller in the cab unplug it and see if it makes a difference. Also check your bulbs including the third brake light on the top of the cab.

Apr 20, 2008 | 01:25 PM

444dieselrod

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Joined: Aug 2004

Posts: 2,417

Likes: 4

From: Braham MN

sounds like a bad ground in the tail light circuit. they backfeed through the brake light feed and into the PCM, it unlocks the TC then. mine does it everynow and then. the plug for all the tail lights on the rear drivers frame near the tailgate gets loose and causes it. try that.

Diesel Rod

Apr 20, 2008 | 05:38 PM

rungunner

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Joined: Dec 2007

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From: MI

Rpm's

Thanks guys, will try your suggestion tommorow.

Apr 24, 2008 | 04:10 PM

rungunner

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Joined: Dec 2007

Posts: 88

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From: MI

Rpm's

You are a genius, took thr 3rd brake lens off and only one burnt out bulb in the center (the other two were dust). Took that out drove to work and the RPM'S were all over the place. Installed three new bulbs and the truck is running great.

Thanks