So i close the back and the latch grabs it and the motor starts to go down but at about half way down the latch releases and the motor stops. Wondering why the latch keeps opening before reaching the bottom

 

It doesn't. Your pull-down unit is being activated by the hatch hook contacting the strikier-sensing switch, but not engaging in the latch. The pull-down motor will only motor down while that striker-sensing switch is being pressed by the hatch hook. In your case once the motor powers down to the point that the hatch contacts the seal the motor stops. To prove it, try lifting up on the hatch while it is powering down. If I'm correct you'll discover the hatch hook wasn't latched. If so, you'll need to investigate why the latch isn't properly latching on the hook. You may need to replace just the latch portion.

Lon

 

when i pull on the hatch while the motor is going down the latch releases and the motor stop pulling.

 

The hatch can't magically unlatch by you lifting on the hatch.It was never properly latched or you wouldn't be able to pull up on it. I sell both the 86-87 and 88-91 style of latch assy on my web site.

Lon

 

here is something interesting. so i take the whole assembly off of the car and i engage the latch and wouldnt you know it doesnt unlatch now like it did in the car. But when the whole assembly is in the car and attached the key lock, the locks position is at a 45 degree angle. could the lock being misalligned like this cause the latch not to grab properly

 

Yes.

Also, if someone slammed the hatch in an attempt to close it that will cause that problem.

Usually after several slams you need to adjust the hook on the lid.

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Happy Racing!