Ill tell you what, if anyone can figure this one out, i will buy you dinner if im ever in your area! Our '99 has a horrible electrical problem throughout the whole dash. This problem only occurs when the gas pedal is pressed far enough to drop the tranny down a gear and the RPMs go up, or under heavy acceleration. Check out the pics below.

PICS TAKEN WHILE DRIVING: (dont try this at home )

Exhibit #1. This is what the instrument panel does when you accelerate, or open throttle enough to drop down a gear. But thats not all!!! The A/C blows really hard, the radio cuts off, the bright headlights engage, and the instrument panel lights up TWICE its normal brightness!


Exhibit #2. After the initial surge, all the gauges MAX OUT. Notice the brightness between the 2 pics? Exhibit 1 is twice the brightness of exhibit 2. After the gauges max out, everything goes back to normal.


There are no driveability issues with the truck what so ever. It drives fine, the engine is smooth, and the trans works perfect...while these electrical problems are occuring.

Has anyone seen this on our trucks before, or have any ideas why this is happening? Ex, Nav, F150-250-350, etc? Remember, a dinner is on the line here!

Thank you in advance!

 

My guess, Voltage Regulator. Not sure where it is on the Expy, but my 92 Crown Vic did the same thing and it was the VR.

 

You sir, get a free dinner! I searched for regulator problems, and i came up on this thread. https://www.ford-trucks.com/forums/s...or#post3534778 Very nice! Ill be replacing the alternator then. Thank you!

EDIT: I see you are in NY. Ill be making a trip out there sometime to visit my fiancees family. Do you live near LI? I hear there are some great pizza places out there

 

No dinner nessesary, just glad to help!

I live about about as far from L.I. as you can get and still be in NY (350 miles)

 

awesome, tell us if it really worked.

 

I have an 01 with similar issues, isnt the VR built in to the Alternator?

So, if I replace the alternator, I can fix the issue?

 

I believe so. I personally havent seen an external voltage regulator on anything but older cars.

 

Damn, and I was getting hungry. I concur with the Voltage Regulator diagnosis and the alternator replacement.

 

A brand new Autolite alternator from Kragen fixed it! Is it just me, or does it feel like a car has more power after you put in a new alternator?

 

Assuming you disconnected the battery, the computer is relearning its operating parameters. Since you'd been running with a compromised electrical system, the adaptive strategies employed by the PCM were likely pretty far out of whack.

Steve

 

Hey Steve,

Thanks for the reply. Yep i disconnected the negative lead first, and always being safe, i disconnected the positive. I alwys disconnect the battery in every car i work on before i do any kind of work what so ever. Well, except brakes and stuff The "service engine soon" light is still on after a day of driving. When will the computer kick that thing off, or will i need to reset it myself?

 

Might need to read the code.