My trigger switch doesn't seem to be working. I cannot change the display from total mileage. I can hold the switch down and turn on the ignition to go to Diagnostic, but it won't advance beyond that. It got a wash at the dealer, but was working on the way home as I reset trip A when I filled up. Looked up the part number and it says it's 71500236, but when I do a search on some dealer sites only 71500236A shows up. Is that the right part?