out of my depth!

[urbantuckerman]

hi, i'm a competent mechanic but frankly electronics are my weak point! I'm currently in France in my 1992 Ford transit. On the way here the fuel and temp gauges stopped working. A bit of research pinpointed the problem to a faulty (common) ballast. As i understand it this is basically a resistor which regulates the alternator voltage and prevents the gauges rising and falling with the engine revs. I've taken the gauges apart and found the component. It has 'aa ab-c2a 044269' printed on it.

I'm a bit impoverished at the moment and whilst i'll be able to replace the clocks cheaply in the uk i won't really be able to afford it until i get there. I also much prefer to fix things rather than throw them away!

can anyone please suggest a commonly available component i could solder in to replace the faulty part (i can manage that!).

Thanks!

 

[NuLED]

Are you sure you are asking on the right website? Maybe searching on some auto mechanic website would give you better results?

 

[john monks]

I think what you are looking at is a form of regulator for the gauges. It works with heat and it has a resistor wrapped around a bimetal strip that turns on and off. This would be a little difficult to explain fully but the bottom line is I think you need to get another one out of an old car. Maybe an auto mechanic website would help.

 

[JMW]

Google does not show any results for aa ab-c2a 044269.
What is the alternator charging at? Fuel gauge, just keep track of the "kilometerage" (French for mileage). If the alternator is not charging or overcharging, I only recommend exact replacements. In general if the engineers could have used a cheaper item, they would have. Trying to bypass or rigging something is more than likely to leave you stranded with not only the original problem, but at least one new one. If the alternator is doing its thing, check it twice a day, and you'll be fine.
I'm concerned that this "ballast failure" is a symptom rather than a cause.

 

[duke37]

I think there is some confusion here!

The alternator has its own regulator and produces between 13.8 and 14.4 volts. It will do this above tickover and on commercial vehicles at tickover also.

The regulator for the gauges is to give a correct reading if the battery is not being charged. John Monks described how they work although modern ones may be solid state.

You could doubtless make a linear regulator with a heat sink but would need to find the correct voltage. The development of such a circuit would take time and effort. Safety would need to be considered.

The Ford is a common vehicle and a trip to the breakers would be my preferred option.

 

[urbantuckerman]

thanks for everyone's input! regarding the function of the ballast, i'm basically paraphrasing info from a couple of transit van forums, but i haven't got a really definative answer.

I've lined up set of clocks off a mate in the uk, which will have the added bonus of a mph speedometer. so i guess i'll go down that route!

thanks again!

 

[Y2KEDDIE]

I have a similar problem with my tachometer on my 94 Nissan, SEV6 pickup. The tach intermitently pegs itself and sometimes goes back to indicating the right RPM. it does this with the engine running,or not running with just the ignition switch on. I 've looked high and low to find the ballast resistor. The wiring diagram shows it as a resistor in series with the tach modue, but I have no pictorial of it's location. I't might be in the battery lead as a resistive lead; I'm not sure. It's driving me crazy. I hate to give up, I've been looking for 5 years now!