double check your wire connections. you also could have a pinched/broken wire not allowing all the voltage to get thru. As TechII mentioned testing voltages should show you what wire(s) are not getting 24vlts.
Also you wire repairs should be soldered and use heat shrink tubing to keep them from corroding. Seen a lot of them like this, then the corrosion eats away at the wires inside the plastic casing.