Dewalt 18 volt cordless hammer drill

First before you open the tool ground yourself. The switch is probably static sensitive. Now open the tool and check for wires that may have come loose from the switch, or motor brush area. If no bad wires make sure the switch terminals are ok (not broken or bent and are tight enough to make contact with the batery terminals). Next check the brushes and make sure they move freely in the brush holders. You didn't state the model so it may not have brushes you can access. If all that is good disconnect the motor from the switch and secure the motor in a vise. Take wires with alligator clips and connect the battery directly to the motor for just a second to see if it runs. If the motor runs you have a bad switch assuming your battery is charged.

This replacement battery was a great find. We searched for batteries for our Dewalt drill and this is the only site(www.drill-battery.co.uk) that had it and at a good price. Works fantastic and is a great deal.

web search-dewalt dc988 schematics-click on 2nd site,{parts list and diagrams

I had same issue with Metabo hammer drill. It was faulty triggrer. Replace it and it shoul be fine.
Juraj

Test the brushes by catching it in a stalled condition when you have it triggered, then rotate it slightly. If it takes off suspect the brushes or a dead segment on the comutator.

If it doesn't respond to this, then consider the VSR trigger... open it and test by bypassing it when in stalled condition...

if i'm confused i'm sorry, but don't confuse and impact driver with a hammer drill

2 different tools altogether

Go to Dewaltservicenet.com and in the middle of the page towards the bottom type in your model number and it will take you to a page where the schematics are.

Had the same problem figured out it was a wiring problem with the trigger, works good now.

You need to replace the trigger unit to correcxt the problem.

We.ve the same problem with those Chinese batteries and find that this problem is quite wide spread with many brands using these batteries. I'm speaking from experience with our battery factories. No quality control!