Replace that twisted wire connection with a proper connection or you will have trouble in the future.
Best I have found is using solder splices, these things are awesome, you slip them on, heat gun them, the low temp solder melts and joins the wires , the tubing shrinks as the glue inside strain reliefs and waterproofs the joint. These have proven 100% reliable, just buy the right size for the wires your splicing.
You can get them many places including Amazon
Amazon.com: 22-18 Solder Splice : Industrial & Scientific
www.amazon.com