Jeep - what is that thing under the hood?

[Betty]

Question for jeep people and/or mechanics. This photo is under the hood, over by the battery. See that black plug thing over on the right? It wasn't plugged in... for how long? If we follow the wire, it goes into a wire harness. Plugging it in doesn't seem to have any effect one way or another. What is it?

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/412409_3979795538051_1375540822_3635641_816826828_ o.jpg

[DreadPirateRoberts]

The black plug is a relay. What year is the jeep? TJ ?

It doesn't look stock. What has been added aftermarket? winch ? lights? alarm?

[Betty]

It's an 03 TJ. Winch added... or at least it was until it it was broken a few weeks ago.

Someone else suggested it was perhaps, for a rear window wiper for a hard top (which we don't have) or fog lights. We aren't the original owners - maybe it had something like that before we got it.

[Betty]

My husband thinks it's stock something as it appears to be part of the factory harness.

[DreadPirateRoberts]

Do you have the owner's manual? Do they make any mention of daytime running lights?

[Betty]

Do you have the owner's manual? Do they make any mention of daytime running lights?

He shook his head and made a sort of incoherent noise which I take to mean no. ha ha ha :D

He does have a Haynes manual which shows it but doesn't say what it's for apparently.

[Moonliner]

I called in the heavy artillery (http://www.reddit.com/r/jeep). We should have our answer shortly....


Or even faster....

That's the ECU - the "Engine Control Unit". The unit converts the distributor's magnetic signal to the necessary signal to fire the coil. If it fails the jeep will not run. You can get a replacement at any major parts store by asking for the ignition control module. If you hook up an HEI (High Energy Ignition) system you will not need it at all and can get rid of it and all the associated wiring (aside from the main igition feed wire that will need to be hooked up to the HEI distributor).

[Moonliner]

Woops. I think this might be the better answer...


You talking about the ones attached to the silver ECU or the one that is by itself on the painted surface? Because that one (on the painted surface) is just a fog light or some such thing relay. Aftermarket it looks. Wouldn't surprise me if the device it was attached to is now long gone.

[Betty]

First off - Reddit has a jeep forum! TIL!

And yes - talking about the the one off by itself on the right. Hey - at least it wasn't something important that's been unplugged.

[DreadPirateRoberts]

When the relay is unplugged, does the cigarette lighter work? How about the heater/ac?

Are there any check engine lights on?

[Moonliner]

First off - Reddit has a jeep forum! TIL!

And yes - talking about the the one off by itself on the right. Hey - at least it wasn't something important that's been unplugged.

Reddit has thousands of forums... Try www.reddit.com/r/"whatever"

www.reddit.com/r/bacon
www.reddit.com/r/disney
www.reddit.com/r/downunder
www.reddit.com/r/sharpies
www.reddit.com/r/squiward

If you don't find what you are interested in you can always start a new one.

[Betty]

Reddit has thousands of forums... Try www.reddit.com/r/"whatever"

www.reddit.com/r/bacon
www.reddit.com/r/disney
www.reddit.com/r/downunder
www.reddit.com/r/sharpies
www.reddit.com/r/squiward

If you don't find what you are interested in you can always start a new one.

I converted from FARK and haven't looked back. I don't know why I never thought to look up Jeep on it. And so many other things. It's a time sink I don't want to be saved from. ;)

[Betty]

When the relay is unplugged, does the cigarette lighter work? How about the heater/ac?

Are there any check engine lights on?

Well.... I say this sort of laughing... It's a Jeep and over time, not everything works as well as it once did. The radio occasionally goes out and the heater, which once worked great, had something nibbled on by squirrels* and now blows out all the vents instead of whatever one you have it on.

*Do not put jeep between the place the squirrels live and a bird feeder with sunflower seeds. When the squirrels get scared, they take cover in the nearest thing... the jeep. You don't want to see half a dozen squirrels run from the inside and from under the hood. They nibbled the frickin' seat and a few other spots inside... and under the hood as well. Which sucks. I really enjoyed having a bird feeder and was wanting to add a birdbath to my little flower garden to go with it.