Hyundai Repair: 2001 Santa Fe Speedometer, backup lights, deep cuts

Question
I have a 2001 Santa Fe V6, at about 58,000 miles the speedometer started cutting out intermittley, the dealer replace the speed sensor and the speedometer itself, then they  said it was a short in the towbar wiring, they disconnected that and it seemed to work well for about 3 months, it just started to cut out again, seems like it cuts out when I apply the brakes, and sometime the turn signal, I checked the wiring where they disconnected the towbar wiring, there is some deep cuts in the wires, they had them taped, do you think these cut could be causing the problem, they are not cut in half or broken, just deep cuts where the towbar wiring was connected, looks like they used some thing like the 3M quick splice to connect the towbar wires, any help on this will be appreciated.
Thanks,
John

Answer
Hello John,
I think you have a poor ground problem. Ground connection on the lower/Left corner (Left side of the pedals) is supplying ground to cluster, tachometer, backup lights, room lamp and multifunction switch. Check that ground connection.You need to remove lower/left trim to have access. Even if it is tight, remove it ,clean the connector and the body where it touches and reinstall.