Offshoreonly.com - Trim Indicator Gauge not Working

Over the last two weeks I have been troubleshooting why my starboard trim indicator gauge was not working. When I looked at the actual trim sender mounted to my Bravo 1 drive I saw one of the wires going into the side of the sender rotted away. After cutting out the bad section I was able to splice some new wiring but was not able to save the trim sender so I ordered a new one which also came with the other side trim switch. I made sure the wire going to the trim gauge signal post had polarity. What I did not do was also check the other wire which I understand just to be a ground wire. So I spliced in the new trim indicator and still no working gauge. I then decided to check polarity on the ground wire going into my engine bay. What I found was an open ground indicating to me that was why the gauge was not working. To prove this was the case I jumped the ground wire from the trim indicator to one of the stainless steel grounding wires on my drive and now the gauge is working. I know the proper way around this problem would have been not to cut the wires from the new trim indicator but to route them thru the drive into the engine compartment but this would have meant I would have to remove the drive, remove the rubber bellows to get the wire routed thru. I am trying to avoid doing this right now. Would it be okay just to splice in a grounding wire from the trim indicator to one of the grounding connections on the drive? I definitely have a break in the ground wire from the back of my drive into where it connects to a pigtail connector in my engine compartment. I have a feeling it is where the wire has a strain relief that broke off and without removing the drive I will not be able to get to it.