Editing Forums/Z31P/z31-repairs-forums electronics/Warning lamps when fan comes on

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|op_user=kbone84
|op_date=2019-01-19 20:01:01
|post_count=4
|archive_url=/Z31performance_archive/forum/z31-repairs-forums/electronics/542152-warning-lamps-when-fan-comes-on.html
}}

'''kbone84:''' <small>(2019-01-19 20:01:01)</small>

Hello Everyone, I recently installed an electric fan. I used the AC wire (at the pressure switch in the engine compartment) as the switched 12v source to my fan relay. The fan operates as it should, but when the fan comes on my headlight and coolant warning lights turn on. They turn off with the fan as well. It seems like the fan relay is activating the warning lams when the relay coil grounds? Is there a different switched power source under the hood I should use instead? Thank You!!!

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'''Z_Karma:''' <small>(2019-01-23 00:06:41)</small>

That source might have used a isolated ground in it's circuit. Nissan did some weird floating grounds with some stuff in these cars.

It's usually a sound idea to run your own wires for aftermarket accessories unless you understand the circuits you are tapping into.

If you use a thermostatic switch with your relay, you don't necessarily need a switched source. I use a fused wire right from the battery terminal

as the [https://www.amazon.com/American-Volt-Adjustable-Thermostat-Temperature/dp/B01E52O5DG?tag=z31performance-20 thermostatic switch will control the fan.] They suggest you use a switched source, but I've personally not had any problems with the taurus fan

running very long past when the engine shuts down. I have the temp probe tucked into the radiator fins at the top of the radiator near the hose fitting.

If i did have to locate a switched 12V signal i trusted, i would use the one from the cigarette lighter and route it to the relay.

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'''kbone84:''' <small>(2019-01-23 04:30:17)</small>

Thank you Z_Karma. I wired it to the battery as you advised, and you're right- it doesn't run very long after shutting down the engine. I was concerned it would drain the battery but I don't think it will be an issue. If I get a wild hair one day, maybe I'll connect the switched power from the lighter. Thanks again!!

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'''mwolvinm:''' <small>(2019-01-23 18:03:22)</small>

I imagine the direction to put it on a switched circuit is for safety reasons so that you have a method of securing the fan off when you are working around it. I would recommend pulling the fuse for the fan in those situations "just in case". Just remember to put it back when you're done.