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2002 Focus instruments flatline then car dies

Yesterday my 2002 Ford Focus SE Zetec wagon (140k) died at a stoplight. Before that, the radio would turn off and on like it was possessed. The last five miles before it conked out, the fuel gauge and speedometer dropped to zero (ie same as with key-out). Waited two hours and was able to drive it two blocks home but the same symptoms w/instruments occurred. Battery measured 12.0v @ home.

The alternator is the first suspect but what else should get replaced? Any guesses as for cost? DIY or take it to a shop? Thanks in advance.

First pull your main battery cables at both ends - battery & starter & especially grounds. Clean everything up & get it back on good & tight. Then take it to an auto parts store - most will check the battery & charging system for free. There’s no need to guess.

If you mean that the battery actually measured 12V then it is probably no good - or its connections are no good. A fully charged battery should be at about 12.6V By the time you get down below about 12.4V you have a problem. With the car running you should be reading something like 13.5-15V at the battery. Then again, the auto parts store service is free & their equipment can do extensive testing, including load testing. So its easiest to just do that.

I’d have the battery tested before anything else. It may be shot. Most auto parts stores will test the battery free. Ask for a “load test.” Have the alternator tested too, but right now my money is on the battery.

Was the alternator light on at all?

The battery measured 12.0v with the engine off. The alternator light never lit up but when the instrument cluster went haywire, the abs and airbag lights turned on briefly (<1min). The battery has a date code of 10/09 with a 36mo warranty so that’s why my first suspect was the alternator.

Will get load test @ local shop after I clean up a few more fugly looking grounds. Battery terminals looked clean but some grounds looked corroded. Hopefully the battery will take enough of a charge to drive two blocks to the auto parts store.

I trickle charged the battery for 12hrs and drove it uneventfully to the parts shop two blocks away. The load tester reported a good but undercharged battery and a bad alternator (specifically the diodes were good but the regulator was bad). The battery voltage when the car was idling was low but I didn’t get an exact number.

A used alternator from an ebay wreck (~120k) is on its way but probably won’t arrive until Friday or maybe Monday. Once that one is installed and working, I will rebuild the original if possible so when it conks out I can swap them.

Thanks for the help so far!

The alternator from the wreck (110k) arrived Wednesday and the dead one was removed with much effort. The serpentine belt unwrapped and needed to be restrung. We also had to unbolt the engine mount. This morning the sun came out and I was shoehorning in the new alternator when a neighbor jumped in and had everything finished inside of 30 minutes. It turns out his dad raced at a local speedway and he has worked on cars since he was a kid. I swear he could have done it blindfolded, drunk and with both hands tied behind his back.

Thanks again to everyone for their help in making my first DIY a success! Hopefully I can someday return the favor to the community.

Thanks much for the follow-up. Many people never bother.

Where is a good source for alternator rebuild kits or would this be a bad idea? Do DIY rebuilds last? I repair stereo equipment for fun so something like this would probably be doable.

Depending on the alternator, you can get them at most auto-parts places. Check on-line for better prices and availability, as you’re not in a hurry.

Rebuild kits normally consist of a regulator, sometimes the whole diode assembly and brushes. They can be a pain to change, and a lot of places don’t like to (or won’t) sell them, as they’d rather sell you an alternator with some kind of “lifetime” guarantee. The better kits also include new screws, bearings and the like, and run about half the cost of a replacement rebuilt alternator.

You’ll need the type (Bosch?) and model to get the right parts.

Edit: Summit Racing ( does sell some rebuild kits.
Best of luck

Cig’s advise is good. Things like this are usually a BAD CONNECTION somewhere in the electrical system…Start at the battery, the alternator, all the ground connections on both ends, work your way out to the fuse block and ignition switch…That 12.0 volt reading indicates a battery and alternator test should be performed…

I once read that 12 volts is 75% discharged. Hmmmmmm…

Re: @12v it just started and even then the instrument cluster was erratic. Starting from when I first noticed the radio acting goofy, I drove roughly 30 miles before it died. As mentioned previously, none of the idiot lights (alternator/check engine/etc) lit. Next time I’ll watch for the radio shutting off and the little LED behind the station buttons lighting up. Dunno what the LED signifies but I had never seen it on before.

Looks like my victory dance was a bit premature.

This morning (8:43am to be specific) the radio was acting up as it did before. The battery measured 12.75v engine off and 14.92v running. The Haynes manual says off should be 12.6v or less and running should be 14.7v or less. Strangely the clock on the radio had frozen at 8:14 and it was cold and parked at that time. I disconnected the battery, unbolted everything attached to both battery terminals, wire-brushed them again and reconnected everything. The battery voltages didn’t change but the radio came back to life.

When I replaced the alternator, I cleaned the big positive lead eyelet with a wire brush. There was some oxidation on the wire that connected to said eyelet. The wreck alternator was sold as working but it looks like I missed something. Next I’ll take it to the parts store and have them run the electrical test again. It isn’t having any problems starting and the instruments haven’t flatlined again (yet).

Since the running voltage is slightly high and the radio is acting up as it did before, could this mean I missed a bad connection someplace?

I wouldn’t worry about the battery or alternator at this point. Your numbers are fine.

I would worry about those main cables. Slice off some of the insulation and look underneath for hidden corrosion. Search out every single ground point for the negative cable & deal with those completely.

You might also get a gander at the condition of the main junction box under the hood with all of the relays & fuses. Try to get a look underneath as the wires probably go in through the bottom.

The battery and charging system appear to be running great. They aren’t the cause of the trouble. If the radio is now the only thing that is having a problem then you need to verify that power is getting to it ok. If that checks out and the grounding for the radio is ok then the radio has an internal problem. Check out Ebay for a replacement unit.

I was concerned because the radio acted up before the alternator died. The radio worked fine today during roughly 45 minutes of in-town driving so I might get brave Sunday and drive to Chicago.

I’ve heard that I should use dielectric grease to prevent oxidation after cleaning. Should I do this on the battery terminals or is grease more for sealed connectors? Petroleum jelly was also suggested but that feels like a bad idea.

Thanks again.

Dielectric grease would be the better of the two. I personally wouldn’t use petroleum jelly, but they use dielectric on all terminals in boats (and I always did in mine), so it’s got to be good, right? You don’t need to clean them every day, either. A quick go over every few months should be plenty…in fact, much more than most cars get (haven’t done mine ever in my 01 and 04).

I think you need to have a serious look at that radio. From what I’ve read, it seems to be the consistent problem. It could also be causing a drain on the system, and all kinds of weird thing happen when wires short. There’s nothing wrong with the battery nor the charging system, and that radio keeps going nutty.

Edit: To my way of thinking, this is the kind of obvious thing I always look for. Something strange, that only happens every so often, or happens right before another important event (like the car dying, or gauge cluster going out). Same way with just about all troubleshooting, I believe.


CRC makes a battery terminal protector ( I use it, but I can’t say whether its more effective than just coating the terminals with something else. Of course, I also went a long time in life using nothing and had very few problems too. I just saw it once so I bought it. One can seems that it will last a lifetime.