Battery Size & Relay


I have a 2000 Dodge Dakota and when I shut it off a few days ago I noticed that the electric cooling fan on the radiator was still running. It ran for about 15 minutes while I was hunting down tools to unhook the battery terminals so the battery wouldn’t drain.

I read online that it was the Radiator Fan Relay which I believe was just loose. I reconnected the battery and it was still running…I tapped on the relay and it shut off. The fan has not come back on since then.

However the battery in my truck barely had enough juice to start it yesterday, I put it on a battery charger and it was dead again today.

I bought the truck used a few years and the battery is the same one never been replaced. However I don’t know if they even had the correct size battery in the truck. What size is the correct one for my 2000 Dodge Dakota. The writing on the original is not readable.

I replaced the battery with another one that I had that is group size 37 with 600 CCA.

What size battery do I actually need and I am going to leave this battery in overnight to see if something else is possible draining my battery while it is turned off. But I don’;t know that that would be since the fan is no longer running when vehicle is shut off?

Just rereading my post. I think the battery that was the original was just older and the fan running drained what little life it had in it still.

Any place that sells batteries will know what you need . Even the Walmart web site has a section where you list your vehicle and it will show what battery is specified.

Replace that fan relay as a start. It is sticking.

Take whatever you will use to an auto parts store to be tested. Replace if needed.

IF the truck runs the battery down overnight, you have a parasitic drain that must be found and fixed. Eric the Car Guy on Youtube has a pretty good video on how to do that. BUT, if the truck has an aftermarket radio, remote starter or alarm, you can assume one of those is the drain. Unplug it (or them) and see if the drain goes away

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Not for sure on your 2000 Dakota, but some vehicles will have an electric fan that may continue to run after turning the engine off. These are not automatically turned off with the key. This may not be a problem.

Tapping the relay and making it turn off would lead me the same direction as @Mustangman Replace the relay, and have the battery tested. If the battery is original, it very likely needs replaced anyway.