Jump to content

voltage drop with cooling fans cycle

Recommended Posts

Back story 142k I changed the alternator 8 months ago because it dead. The battery is 2 years old. I checked the voltage and it seems to all be good once I changed the alternator. but in that past two days it just started doing this. At idle with the park lights on warming up the car everything seems fine, I put on the blower fan and when the cooling fans cycle there is a crazy drop in voltage in the system, like the the whole dash interior lights turn off and come back on. Its only like two seconds but it's not good. I have not checked it with my voltage meter yet. I was thinking one or both of the cooling fan motors are going because there drawing crazy voltage on the system. I'm I right? has anybody had this problem before?




Link to comment
Share on other sites

Your theory is sound. Also, a bad ground can do weird things like that. For a while mine would turn off all the electrics for a fraction of a second every time I touched the brake pedal. There are many grounds and many are exposed so they corrode and then things get real weird.


Check/clean them (by removing the bolt and cleaning the sheet metal and wire connectors) at the top of each front strut tower, there is one for the engine, one for the intake manifold, one for the transmission. I don't recall for sure, but I would expect one on each side near the headlights, probably down low where they could serve the radiator fans as well as the lights. There are some inside as well, but it is less common for them to be a problem unless you live in the great white north and track a lot of snow and slush inside.

Edited by doublechaz
Link to comment
Share on other sites

I'll check the grounds in NY here, but the car never saw winter it looks like for its life really. no rust or anything.



It's a duralast alternator 90am. I did test it again with everything running and my meter still said 13.95 to 14.10 volts.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

Terms of Use