mikecsti Posted November 1, 2019 Share Posted November 1, 2019 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? thanks Link to comment Share on other sites More sharing options...
doublechaz Posted November 2, 2019 Share Posted November 2, 2019 (edited) 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 November 2, 2019 by doublechaz Link to comment Share on other sites More sharing options...
RumbleRumble Posted November 5, 2019 Share Posted November 5, 2019 What kind of alternator did you use? I would get it bench tested. Link to comment Share on other sites More sharing options...
mikecsti Posted November 6, 2019 Author Share Posted November 6, 2019 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 More sharing options...
RumbleRumble Posted November 7, 2019 Share Posted November 7, 2019 you need to bench test it. It will tell you more than just voltage while the car is running. Link to comment Share on other sites More sharing options...
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