Factory amp&subwoofer

I have a 1999 Explorer Limited ABSOLUTELY LOVE IT. When I bought it, it had an aftermarket stereo head unit in it. They gave me the factory stereo with it which I would like to put back in since I've realized that my explorer has a cd changer, factory amp and subwoofer in it none of which work with the aftermarket head unit and neither do the steering wheel controls for the stereo. However the back of the head unit has 4 connections only 2 of which have pins. The is one that says amp but has no pins. There is 3 harnesses in the dash. I'm curious if they gave me the actual factory HU. The model they gave me is xl2f-18c868-bb. But I don't see how it's supposed to power the factory amp if in fact it is the correct head unit. Any help would be greatly appreciated since I'm absolutely stumped. The only thing I can think is that the factory hu is not in fact the correct one for the factory amp and sub. When I hook up the unit the steering wheel controls and cd changer work but nothing with the amp or sub.

Can I see a picture of the head unit?

If the steering wheel controls work, it should be the right headunit. Only limited Explorers came with Steering wheel controls.

It won't let me post a pic but here's a site of the unit the empty slot on the top right says amp but has no connections. http://m.ebay.ca/itm?itemId=151360533770

Link to pic

http://m.ebay.ca/itm?itemId=151360533770

That's the correct radio for the Limited. that's odd.
Are you sure there are no pins for it in the radio? And that it's not just covered with some plastic?

Could there possibly be a bypass harness which was installed with the aftermarket HU? Just a thought.

drdoom said:

Could there possibly be a bypass harness which was installed with the aftermarket HU? Just a thought.

Click to expand...

Not on a 99, since the amp is built into the head unit. It's just the subwoofer amp that's separate.

I appreciate all the answers and advice. As far as it being covered by plastic I'll have to see if the plastic insert that says all on it acutely has pins behind it. If find it really of if that was the case that would mean it's never been hooked up since it change out of the factory.

It may just be a new radio they gave you.