Five minutes into running tachometer, speedometer and water temperature gauges stop working

CMARTIN89

MEMBER
2004 FORD EXPLORER
4.6L
V8
4WD
AUTOMATIC
160,000 MILES

I start the explorer and then five minutes into running tachometer, speedometer, and water temperature gauges stop working. The parking brake light, high temperature low oil light, and wrench light come on with no change in performance. Then everything goes back to normal. While driving same thing happens. About twenty to forty five minutes latter engine fail safe shows up on the message center. The SUV just had a new wiring harness put in. What could this be?

9 Replies

CARADIODOC

MECHANIC
33,873 POSTS

Your mechanic will connect a scanner to look at what the various computers are seeing and responding to, but it is important to understand the data has to be observed while the problem is occurring, otherwise everything is going to look normal.

There are two good suspects when so many different systems are affected. The first is the instrument cluster is Ford's most intelligent, (complicated) computer module and it affects all the other computers on the vehicle. Failures are fairly common. The charging system is also related to every computer. Low system voltage will confuse many of the computers and make them do weird things. At the mileage you listed, worn brushes inside the generator can be expected, and those will always cause intermittent operation for weeks or months before they fail completely. Your mechanic can perform a test on the charging system, but that also must be done while the problem is occurring for the results to be valid.

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Tuesday, January 3rd, 2017 AT 1:22 PM

DOCFIXIT

MECHANIC
18,828 POSTS

Which harness was replaced? Why? Have you taken to auto parts to have scanned for codes?

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Tuesday, January 3rd, 2017 AT 1:24 PM

CMARTIN89

MEMBER
5 POSTS

As far as I know the main harness under the hood was replaced. I took it the auto parts store and had them test it wile the problem was happening and the only error code that popped up was for the
T. P.S. The battery is new and the alternator was charging good, mind you the cluster was not working at the time of test. I'm thinking that the shop the car lot took it to failed to sink the computers after the wiring was done. When I checked the fuses about 60% of them were blown or burnt. I replaced them all. I just use it for work but its quite annoying going down the highway then no speed or even rpm. I miss the days when all you had to do was remove the broken part and either rebuild it or put a new one on. Now its all computers. My next work truck is going to be a carburetor .

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Thursday, January 5th, 2017 AT 5:37 AM

CMARTIN89

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5 POSTS

Also, thank you for the help

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Thursday, January 5th, 2017 AT 5:38 AM

CARADIODOC

MECHANIC
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There's nothing to do as far as syncing computers when the wiring harness between them is replaced. They don't talk back and forth to each other when the ignition switch is off, and when it is turned on, they have no idea the harness had been disconnected. That only pertains to a few under-hood computers anyway. Be aware too that new wiring harnesses are extremely expensive. We rarely resort to replacing one unless it was badly damaged in a crash, or it is under warranty and the manufacturer is supplying it. Knowing that might help you in assessing the type of repair that was done.

My vote at this point is for a problem on the instrument cluster. That's pretty common given how complicated they are.

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Thursday, January 5th, 2017 AT 1:22 PM

CMARTIN89

MEMBER
5 POSTS

I'm not paying for the repairs, the car lot is. But if I can fix it myself id rather do that. The car lot is kind of cheap. I only paid $2400 for it. I was hoping it would be a pull and replace problem. Not yank the dash problem. I think if I'm going to do that I'm going to get rid of the drive by wire and find linkage or cut my losses. Turn it in to a drag suv or something. I just found a 1977 f150 for sale. It would be better for work any way. Thank you for the help.

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Thursday, January 5th, 2017 AT 3:27 PM

CARADIODOC

MECHANIC
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Let me know when this is solved.

Personally, I'd rather see you in the '77 model. Until recently my daily driver has been a rusty trusty '88 Grand Caravan with only a very reliable Engine Computer, and no others. In the summer I still drive an '80 Plymouth Volare with NO computers. I have a 2014 Dodge truck that needs a computer for every possible thing, from roasting my butt to running a power window down. I'm so nervous about what it is going to cost in the future, since I keep my vehicles until they fall apart, because the manufacturers have built in too many tricks that require computers to be programmed by only the dealers. I'm a mechanic and an electrical expert. I should not have to run to the dealer to have my vehicle fixed, (even though they still like me).

By the way, any rust-free '88 Grand Caravans with 15" wheels running around where you are? Mine is so rusty, the carpet is the only thing holding the front and rear together!

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Thursday, January 5th, 2017 AT 4:10 PM

CMARTIN89

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My first truck was a '77 F150. I paid $500 for it at a pawn shop. It had a 351m c6 trans and a ford 9" diff. Hooker headers and a Holly 600 cfm carb. The original Cherry Bomb glass packs with no strait pipe. I Never got a chance to get into the engine. I had a land lord that had it towed while I was at work because it was too loud. Never told me where it was and no tow yard around had it. I spent a year looking for it with no luck. And I'll look around and if I see an '88 Grand Caravan I'll let you know.

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Friday, January 6th, 2017 AT 6:14 AM