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Electronics surge after alternator replacement

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Joined: Mon Mar 05, 2018 11:32 am
Vehicle: 2006 Ford Five Hundred SEL FWD

Electronics surge after alternator replacement

Post by Brack1 » Mon Mar 05, 2018 12:05 pm

Hello all,

I'm sorry for the long story, but I've got a baby on the way in May and I need to sell my 2006 Five Hundred SEL FWD with 116,000 miles because we "upgraded" to a minivan, but I can't figure out this problem and I don't think I can sell the car in good conscience until I can fix it or at least explain what could be wrong.

Back in mid-December the voltage regulator went out on my alternator, it was a lot of fun because it happened 50 miles from home in the dark and the way I knew something was wrong is that I'd get a check charging system message, then ALL electric systems would turn off including headlights. Found out that it was the computer protecting itself against more than 19 volts and shutting everything besides the engine down. I did some research and found the alternator to be the cause. I replaced the alternator with a unit from O'Reilly's the next Saturday, the electronics no longer shut-down, but the check charging system light comes on intermittently. Did some more research, found out that can happen with non-OEM alternators due to data transmission incompatibilities or some such nonsense. Got tired of messing with it, sent it to a mechanic and said to put a new Ford alternator in it. They did this and the check charging system light turned off. Great, right? Well on the drive home, I took the following video: https://youtu.be/d3WIWm3W8GI

It's hard to see the lights pulsating, but if you turn up the audio, you can hear the HVAC blower-motor pulsating badly. Annoyed, I returned the car to the mechanic, who agreed something was wrong, and they decided to replace the alternator with a different one from Ford. Same thing happened with new alternator and they said it had to be the PCM, but take it to a dealership and they could figure it out for sure. Took it to the dealership and told them what was happening, a week later they said they weren't 100% sure and even had to open a case with Ford engineers, but they thought it was either the PCM or the instrument cluster but since neither was still available from their supplier, they couldn't fix it and charged me $100. I didn't think it was possible to be the cluster, so I found a PCM repair service online for $150. They got good reviews and I figured it was my best chance as a "new" PCM is at least $200 plus at least a $120 dealership fee for programming. The repair place tested the PCM and could find nothing wrong. So I'm back to square one with this issue. I've looked at instrument clusters, I can find them for under $100 and replacement does not look hard, but I'll need to have it programmed as well which is at least $120. So before I dropped another $200 on top of the $900 I've already spent trying to fix this #$&*ing thing, I thought I'd ask around a little first. Thanks!

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