About 6 months ago I bought a Ford Winstar SEL van (2000) with a little less than 100k on the clock. I have had no problems with it automotively. However when I bought it the tire pressure warning light was on. No problem I thought, I will top up the tires and reset it, which I did. Over the next few weeks more warning lights started coming on and off at random - parking brake, ABS and airbag. I know that it is a fault as why else would the brake and airbag lights suddenly come on (together) as I am driving along. Soon after, the needles on my dials started going crazy - revs, speed, temp and fuel at random do mad, chaotic movements. Sometimes they come to rest at the correct reading (I kind off calibrate my speedo using my tomtom), at zero (but I am still moving), at maximum/off the scale, or at some arbitary position on the dial. These days I reckon I spend in excess of 50% of my motoring time with rogue lights on and erractic movement or ilogical positioning of the needles. In a rather pathetic attempt to cure the gremlin I disconnected the battery for a while - no joy. My son has found that a sharp tap/thump on the glass brings the needles back to a sensible/accurate position. The novelty has begun to wear off. Any ideas how this can be cured? Btw - I rigged up trailer lights some time ago, but I don’t think that bit of vehicle maintenance coincided with appearance of the fault.
Might be a bad ground somewhere, as that’s what all electrical components have in common. A strap may be missing.
A cheap approach to diagnose this would be to bridge the various ground points (usually pieces of sheetmetal) with a test cable* with roach clips on each end to see if if fixes it.
I (in car rental industry) had a customer complain about all sorts of lights flashing, speedometer going to zero while he’s driving, etc. Sounds similar to the symptoms you have. A big difference to keep in mind here (as a disclaimer!): This was on a 2012 Focus, not a 2000 Windstar.
I took the car to the dealer, as it should be under warranty, and they said the car had a loose terminal on the battery. Righty-tighty, and it was done 25 minutes after I dropped it off.
Next customer said the same symptoms just popped up. I take it back to the dealer, tell them “I dunno - maybe the terminal came loose again.” Next day, I get a call to head back into the shop so the service writer can show me something. The plastic part of the wheel well gone missing, exposing the wires that would normally be behind it to the moving parts of the suspension assembly. Yay! So yeah, those wires were all chewed up.
Long story short, you may very well have some chewed up wires somewhere, causing a good short. Now, where would that be? Maybe somewhere close to where your son gives “a sharp tap/thump on the glass.”
Windstars have had electric problems since day one. I have had 4 clusters installed in mine under warranty and the needle still jumps a bit. Can’t buy new, only reman and they are no better.
The interior lights flicking on and off most often comes from a bad ignition switch or a short in a wire in the headliner.
I would respectfully say that if you can make the problem go away by tapping on the instrument cluster, that you have a bad instrument cluster or a loose connection, either internally to it, or at the electrical connector that feeds it.
Ford instrument clusters usually come out fairly easily…Start at the bottom and work your way up. A trim panel may pop out to reveal the screws…Then look for a bad connection to the cluster. A spray-can of contact cleaner may be helpful. 80-90% of electrical/electronic problems turn out to be a bad connection somewhere…