CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Check engine light and indoor light

My 97 Geo Prizm did not pass the Maryland emissions test because the check engine light did not come on when powering up the car. The interior ceiling light is also out of wack, it comes on suddendly while driving then turns off or I bang the ceiling to turn it off. The on/off switch does not work and I cannot set to turn on when the door opens. Are these related? My mechanic said he would charge me hundreds just to take the dashboard apart to look for wiring or light bulb problems. Is there a computer test that he should be running instead?

No, they probably aren’t related.

The ceiling light sounds like a loose/corroded connection or maybe a bad bulb. I’d start by replacing the bulb which might have corroded contacts or a broken filament that makes contact sometimes. Replacing a light bulb is within the capabilities of many normal human beings. A clerk at any chain parts store can point you to a replacement bulb if you bring him the old one. If replacing the bulb doesn’t fix the problem, I’d take a good look at the off-on switch and the wires connected to it. If the wires have slip on connectors, try disconnecting them then reconnecting them – best done one at a time incidentally. Prevents the let’s see did the red wire go to the number one terminal or number three? problem.

And while you are replacing things … there’s this mechanic of yours. Maybe the Geo Prizm is an absolute bear to work on. But your problem is likely just a burnt out Check Engine Light bulb. On most cars, getting to that bulb isn’t a lot of fun, but it shouldn’t cost hundreds of dollars. Of course, if the problem is something other than a burnt out bulb, it could cost quite a lot to fix. Maybe you and he miscommunicated. I hope so. If not, it may be time to look for a replacement mechanic.

I agree with vtcodger2. This is not rocket science, and it’s a Prizm, not a Jaguar. Prizms are Corollas, and they are not that hard to work on. Removing the instrument cluster to check the CEL bulb should not cost hundreds of dollars. I seriously doubt the entire dashboard has to come apart. You could read through the procedure in a Haynes service manual at your local book store and see for yourself.

Fixing this light is important. Not only will the car not pass inspection, you won’t know if there are any other developing problems if the light, which is basically an early warning system, doesn’t work.

Get another opinion from a different mechanic.

Check the fuses. The fuse that provides power for the check engine light may be blown. If your mechanic had wiring diagrams, and knew how to read them, he could tell if it shares power with something else.
Go to Auto Zone, Advance Auto Parts, or Pep Boys and ask them to scan the engine computer for you (free). The scan will reveal if there is some problem with the engine computer system; though, it won’t tell you exactly if the bulb is burned out.

Thank you to all for the ideas. I will follow up and report back.

Thank you…you were right. I replaced the indoor ceiling light myself and problem solved. The old one was obviously worn out at both ends. I took the car to PepBoys and they showed me how the Ck engine light bulb was missing from the panel! They took off the Overdrive light bulb and put it in the check engine light bulb spot and problem solved. The light comes on when I turn on the car, then turns off and stays off. The computer test yielded no codes after that. They charged me 1 hr of labor which I know they did not do because I was watching but…heck, it’s better than the hundreds the previous mechanic was telling me. I’ll be looking for a new mechanic. I don’t know who may have removed that light bulb. Thank you to all!