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2002 F-350 with Triton V-8 - Electrical Issue

This continues on with a posting I made on March 25th, 2009. The link is:


I have a 2002 Ford F-350 XLT Crew Cab with the Triton (not aptly named) V-8. Ever since day one, when both of the front window buttons were pushed up together, the “door open” light and chime would go off. So I thought there was some sort of an electrical issue going on. Of little significance, so I let it go.

Lately though, the following has been happening - all at once. The ABS light flashes, the speedometer bounces around, and the engine stutters - quite badly. I suspect that there is a further electrical-sensor-relay problem. As all of these happen together, I doubt it would be just the ABS, or the fuel system.

New information as of July 27, 2009…

I have had the alternator out and tested. It is fine. As well, I disconnected (isolated) it from the wiring harnesses and started the truck. The problem still continued. So I’ve ruled out the alternator.

A friend hooked up his multi-meter across the battery terminals, and when the aforementioned issues occured, there was a 6-volt AC spike in the electrical system.

A previous reply (refer to link above) thought it could be the speed sensor. Where is this located?

Could it be the computer? How would I know, and if so, how would I reset it?

Any additional thoughts?



I suggest you try cleaning the chassis ground connections Tim. I think the problem may be there.

It’s a little unclear. Does this problem occur randomly; when you push up on both window switches; or under some other conditions?

Overall, I’m betting on a bad battery with an intermittent internal short circuit, or a bad connection at the battery terminals. A remote possibility would be that some heavy load like the starter or headlights is kicking in intermittently because of a bad switch.

It’s difficult to rule anything out completely, but the computer and speed sensor don’t seem very likely unless there is something that points to them that you haven’t mentioned. Is there?

OK. I’ve checked a few of the connections in the engine area. All seem to be OK, but will investigate further. Thx…

The first issue only occurs when I push up on both front window switches.

I’ll change out the battery and report back. It is still the original, but shows no sign of swelling, etc. However, the indicator does hover between green & red. The terminals are clean & tight.

I did notice on another web-site that a Ford Escort has a speedometer needle that was jumping around. This was felt to be due to a faulty speed sensor. However, I’ve got a lot more going on.

You can’t just look at the ground connections and determine they are making good connection. The connections should be removed and cleaned with a soft wire brush and wiped with a cloth. Pay close attention to the connection running between the battery and the chassis.

As you know, the AC voltage you saw is not a good thing and I think the gauges are responding to that. Good job on eliminating the alternator as a possible source of trouble since that is the biggest suspect for this kind of trouble. The next thing is bad grounding. Another possibility for the trouble is a bad connection to the noise suppression capacitor in the power buss wiring, if there is one.

I’ll investigate all of this today. I did tune to AM and rev the engine, but did not notice any increased buzz in the radio. Would the noise suppression capacitor have anything to do with this? Perhaps this test no longer applies now that the alternator has been eliminated as a problem source. Where would this capacitor be located?

Thank for your continued assistance, Cougar.

Update for July 29, 2007:

I went thru all of the grounding connections I could find, about 8 under the hood, and all were OK.

Also, I changed out the battery with a new one to determine if it was the battery causing the issues. The problem still persisted.

Continued assistance would be most appreciated! Thanks guys…

You’re welcome for the help.

Using the AM section of the radio to see if you can pick up extra noise was a good idea.

You may also need to check the grounding under the dash area for a problem. My thinking on this trouble is like this. You stated that one of the problems happens when you run both windows UP at the same time. I am thinking that the extra current needed for the second window is causing a higher voltage drop across a bad ground connection somewhere and that is causing the trouble with the other things you mentioned.

If you can have your friend check the AC voltage across the battery again I would like to see if he can verify the first reading he took. One thing I need to make sure of is if the meter he is using blocks DC voltage when measuring AC voltage. Check the AC voltage across the battery while the car is parked. The meter should see no voltage if the DC is being blocked. We don’t want to chase a ghost here because of the way the meter is designed. Some meters do not block the DC component in the AC mode. If the DC is blocked then measure the AC voltage while you move the two windows up and while the engine is running. See what you read then. Normally any AC voltage across the battery should be well below .1 volt, at any time. If there is always some AC voltage there then it may help to pull some fuses to see where it is coming from.