Did you recheck the plug connections on the box? If the plug isn't seated correctly you can have inconsistant contact with the leads and the wipers won't work all the time. When I fixed mine, I thought I had done something wrong because the wipers would reset back to the start position, but the intermitten setting wasn't working. After pulling it apart and rechecking all my solder connection I realized the plug wasn't seating correctly even though it looked like it was good to go. Once I got that squared away, I haven't had any problems. I used the NEC 22111 relays, but I guess the 3100 are even closer to specs then the 22111. I also replaced all 3 relays at one time.
1999 Rodeo LS 3.2 4X2