Another Bosch heater relay issue but w/ a twist
I was able to repair our 5+ yr old Bosch SHX46 but wanted to add my experience to help other's who might find out the usual heater relay pin resoldering job wasn't the full cure to their dishwasher's problem.
* Problem Description - Dishes still dirty, doesn't seem to heat up as hot as it use to (or not at all), not sure if it even finished the cleaning cycle.
* Internet Search: Seems like about 99% of the time the fix for this problem turned out to be a burnt out solder joint on the Heater Relay that just needs to be resoldered, some have actually replaced the original relay with a beefier 12A relay in place of the OEM 10A model. Cool seems like an easy fix.
* Find: Took apart the front door to remove the control board and sure enough a burnt out solder joint was discovered on the Heater Relay. The Relay's pin seemed to have melted away to barely a nub but I was able to solder some solid copper wire to the nub and testing the 6v relay with a power supply verified it was functional.
* FIX: Reassembled the Bosch with the repaired control board feeling very confident it was fixed but performing a test wash cycle quickly proved otherwise. Next day I went out and picked up a replacement relay thinking maybe the repaired relay pin was not handling the fairly large amount of current the Heater requires. After replacing the relay I decided to measure the relay's coil which should be around 100ohms, it measured as a dead short (hmmm is it a DOA relay). After more troubleshooting of the control board it turned out to be a bad IC chip, a tiny ULN2003AG 8-pin surface mounted chip. This chip operates the relays for the motors, heater and detergent/rinse agent actuator. Removing and resoldering on a replacement surface mounted chip like this without damaging the board traces is kind of a challenging task but I'm happy to report that it all worked out fine and the Bosch is working great again.
** Was all this worth it? Let's think about what the cost difference would have been if this were a Field Service call (I was a Field Service Engineer for nearly 15yrs). Even if I were to charge only what my old employer use to pay me @$40/hr, I spent nearly 8hrs of labor with all the troubleshooting and board repair. I spent about $7.50 for the new relay and chip, markup 7x for the parts and $320 for labor the Total comes out to $372.50 but if I were to charge the $225/hr that my old employer charged the customers that Total jumps up to a whopping $1852.5 (I wasnt repairing dishwashers).
A brand new replacement control board could be purchased for about $150 and just about anyone can install the replacement board on this model within an hour. I spent a total of $7.50 to repair my Bosch, so yes I can honestly say it was well worth it (plus I like tackling challenges like these).
NOTE: This is an example of why some jobs get eliminated. Not a lot of people can troubleshoot and repair at the board level like I did but anybody can be trained to just swap out a control board. These days if your DVD player dies it wouldnt make any sense to pay somebody 4hrs of labor to repair it, it makes more sense to toss it and buy a new one for $49.99