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Dan, Technician
Category: Chevy
Satisfied Customers: 23758
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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2004 Trailblazer Check Gage Light Flickering

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Hello. I have a 2004 Trailblazer with just under 90K miles. Just today the Check Gage light switched on then off for a couple of minutes - the only gage that was "wonky" was the oil pressure gage. I checked the oil level and it is OK. Then the Check Gage light went out and never came back on. The oil pressure gage returned to normal. I have heard horror stories about the electrical system on Trailblazers and I am concerned that this is just the tip of the iceberg. Is there any preventative maintenance I can do to see if this is just one little thing or a bunch of things? I am particularly concerned because I drive at night alot and if the electric system goes out, I will not be able to see! Any help would be much appreciated!!

Welcome to JustAnswer, my name is XXXXX XXXXX I'm here to help get your problem resolved. Ask follow up questions, thanks.


You likely have a oil pressure switch starting to fail........Its up to you if you want to replace it now or wait to see if it continues to happen....Its a cheap part and a quick fix......If there was a actual oil pressure problem it shouldnt go down and up like that. It it was a electrical problem other then the oil pressure guage itself other symptoms would have happened so I wouldnt be too worried about complete electrical failure. Let me know if you have questions, thanks.

Customer: replied 6 years ago.
Hey, Dan - thanks for the quck answer. It is easy to get concerned about things starting to wear out at 90K miles - I have been spoiled with this TB - it has been one of the best vehicles that I have had. I have had Fords and Chevys in the past and I really do like this one the best.

Anyway, is the oil pressure switch easy to do myself? If so, is there somewhere I can find how to do it?

The sensor is right above the oil filter, here is a picture. Let me know if you have questions. Thanks.



Customer: replied 6 years ago.
OK - I realize that it is on top of the filter, but (dumb question) is the sensor something that you just unplug and plug in a new one?
Its screws out so you will need to use a socket or wrench "dont know size off the top of my head". Let me know if you have questions, thanks.
Customer: replied 6 years ago.
Ok - sounds good. I appreciate your assistance. By the way, in reading other forums on the subject of these sensors, even after replacing the gage still acts goofy - but it won't hurt to give it a try. One more question - do you know how much they cost?
About $30 from the parts stores......The guage assemblies in these vehicles have alot of problems too but usually effect more then one guage......If problem continues you will need to have a pressure test done to verify oil pressure isnt low, then test wiring between sensor and cluster and replace wire/cluster depending on what is found. Let me know if you have questions, thanks.
Dan and 3 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Thanks, XXXXX XXXXX you have been very helpful. I appreciate it very much!
I'm happy I could help, let me know if you run into questions. Thanks again.