Advertisement

Dear Jim,

I drive a 1995 Chevy Astrovan (4.3L, V6), and I'm having a serious electrical problem with it.

A few days ago the oil, temperature and gas gauges all stopped working at the same time. A mechanic at the Chevy dealer says there's a short circuit somewhere in the wiring. He says all three "sending units" have been burned out, and now all of them have to be replaced.

But how can I be sure all the gauges are really broken? Could it be something else?

-- Dane Woller

That mechanic might be right, bro, but he could be wrong, too. Sure, when three gauges go out at the same time, there's an electrical problem somewhere that's affecting all of them.

The sending units are electrical components that relay information to those gauges. They're all found in different places: the oil sending unit is hooked into an oil galley (access port) to tell the pressure, the temperature unit is linked to the engine via a water galley, and the gas tank unit works with a float assembly that's a lot like the one in a toilet tank.

All these sending units are relayed to the instrument cluster on the dash. Most likely, you do have a short circuit somewhere in the wiring harness. A short like this could allow the individual sending units to overheat and burn out for good, and that may well be what happened.

It's also possible that one or more of them is fine, but just not working under this malfunctioning electrical system.

Any solid repair is going to start with that wiring harness. It needs to be checked and fixed -- otherwise, any new sending units that get installed will be in danger of the same electrical damage.

Once that's repaired, any sending units that aren't burned out should work again and your gauges should come back to life. If they don't, then the sending units need to be checked individually and replaced if necessary. That'll cost more, brother, but there's no other way.

Keep in mind, too, that the gauges themselves are also suspect, because they can burn out too. Hopefully, they haven't, and your problems can be solved at the wiring harness level.

Tip of the Week:

Speaking of burned out components, here's something to remember about bulbs. If you're changing one yourself, especially a halogen or high-intensity version, don't touch it with your fingers. Use a cloth, because oil from your skin can make that bulb fail long before it should.

Buffalo Jim, owner of Allstate Auto & Marine Repair, writes a weekly column. Send your automotive questions to him at buffalojim@lasvegasniftynickel.com. If Jim picks your question to answer in Nuts & Bolts, you'll also be the proud recipient of a deck of official Buffalo Jim playing cards, presented in a classy, tin box bearing his hairy image.