Bosch / Siemens Dishwasher - Fix No Heat / Random Stops

I have recently came across a 7 year old dishwasher which was on sale because it did not heat and sometimes did not start the program or did not finish it properly. The washer had the model number SN44T580SK/23 however this problem appears to be common for many similar machines. The machine was checked by Siemens service and a repair quote of about 500€ was given for change of main control unit of the machine.

When we ran the machine in different programs, we found out that m ost of the time the quick wash program was working properly. Few times it game the E.02 error on display. Apparently E02 error is listed as "Running without heating" and cause is "Working relay of heating is defective" and repair advice is "Change power module". However the module itself is quoted over 250€ at Siemens parts site.

First thing to check is if the element is in working condition. This can be done simply using an ohm meter. The instructions are as shown in the picture below.

The control module in questionw as EPG60110 with part number 9000376770. Unfortunately, I read that these modules are programmed to the machine model so you need to find a module removed from exactly same model machine or it wont function even if all the part numbers match.

I removed the module from its plastic housing after removing all the connections. It is a very simple operation. It was in perfect condition (it looked like it was manufactured very recently) and there were no cracked solder joints etc. Below is a picture of the module from top:

The problem resistors are located on the lower side near the large tabs where the heater cables are connected. Below is a close up.

The problem relay model was HF7FD 012-1ZPTF(576) . There are 2 relays because the heating element consists of 2 parts. Perhaps quick wash uses both relays to heat up the water faster and therefore it was working more often (assuming one of the relay was working better).

What we did was to go to the local electronics store and buy a replacement relay. The replacement we found was RELPOL RM50-3011-85-1012 (unit cost ~3€). It is not a perfect match but the best available in such short time. You may want to go with an 12A or 16A resistive load relay if you can find it in a size which is suitable. I have to remind here that The HF7FD model was a 6-pin switch however you can replace it with a 5-pin version of a similar switch. There is only about 2mm space on top of the relay. The original HF7FD relay was of size (Depth x Width x Height) 16 x 22 x 16.4 mm. You may be able to fit another with a maximum height of 18mm. But I didn't try this and since the RELPOL switch was smaller, this was no problem at all. Picture below shows the dimensions of the HF7FD relay.

I used a manual solder vacuum pump to remove the solder from the original relays. It was very easy to vacuum the solder since the board has rather large holes compared to legs of the relay. The pump could pull out the solder easily.

After removal, simply cleaned the holes on the board with electronics cleaner and then soldered the RELPOL RM50 to same places leaving 6th hole empty. I am not exactly sure why the relay needed 6th pin actually. It seemed rather redundant.

For now, the machine works perfectly. No doubt the relays will fail again, but at least now we know how to easily fix it.

Golf MK4 Variant V68 Temperature Flap and V71 Recirculation Flap servo motor replacement (without removing dashboard)

The V68 servo controls the cold / hot air mix flap and color coded purple.
Th V71 servo controls the opening / closing of air intake flap.

I had errors for both in my system. The errors would go away for a while after clearing, but come back eventually.

I do not know exactly what was the problem with my V68 servo but I found out that there was a crack in a cogwheel  in V71 servo. The crack can be seen in photo below.

I bought a used V71 servo but later I realized it also had a crack. I eventually solved the issue by replacing the broken part from a cheap chinese copy of it. I removed the cogwheel from the chinese unit and put it inside the original unit. It has been over a year now and no errors yet. Removing the cogwheel require heating the shaft up (without melting the cogwheel) and pushing out. It is easier to work with it when it is really warm.

V68 Temperature Flap Servo Replacement

V68 servo is located in the middle of dash all the way bottom. You will need a 6mm small wrench to be able to screw it out. It is held in place with 3 screws.

Yes, 6mm wrench is the only tool you need for removing the servo. However I strongly recommend removing the side panels of center console before proceeding. Below you can see the footwell vent and the purple arm of the V68 servo. The 3 screws around it are the ones we need to remove. Unfortunately I found no other tool than a simple 6mm wrench fitting to the area.

Once the nuts are removed. You can free the servo by rotating slightly. The arm releases its connection at a certain angle. The cable goes off by squeezing the tabs on sides and pulling out.

The installation is the reverse of the procedure. I bought a used V68 servo, opened it and sprayed the potentiometer with contact grease before installation.

V71 Recirculation Flap Servo Replacement

The V71 servo is at the passenger side and attached with a single 6mm screw. Removing it require removal of the glovebox compartment. The glovebox compartment uses 7 torx screws, one of them is behind the middle console covers. Luckily in my car that piece was broken and I was able to remove the glovebox compartment by only removing 6 of the screws.

You will need a long screwdriver type nut opener since the screw is hidden behind some plastic parts. It is perpendicular and you need to access it from bottom. You can see my screwdriver and hand in the picture below, at middle bottom side. It is not difficult to find the screw once you locate it with your fingers. But it is impossible to see it directly without using some sort of mirror.

It is advised to set the servo to middle position before removal. I have done this by pressing the recirculation button and turning off the ignition when servo was about middle way. You should set the new servo to middle before installation also.

Once the screw is removed, you can wiggle out the servo. Servo has 2 connections one connection goes directly to the main flap and the other one is an arm connected to a secondary flap. The easiest way to remove the secondary flap connection was first removing the screw, then wiggling out the servo and then turn the servo slightly so the arm moves to a better position and use my fingers to push it out..

The installation is the reverse of the removal.