Bosch i-dos -- fixing the detergent drawer

quietsailor · 02-02-2023 6:12pm #1

Hello folks,

I've gotten a lot of help to fix things around the house from the threads in this section so I hope this pays some of that help back!

We have one of the bossch washing machines that weighs the load and uses that plus you telling it how dirty the clothes are, to meter in the detergent and softener. It was a great machine for the last 5 years, being ran several time a week as we have two small boys but it started flashing an alarm that the detergent drawer (ie the two pumps) weren't working.

The drawer has a set of contacts at the back and they looked very corroded so I looked at buying both sides of the connection, ie the drawer and correspoding terminal block ---- that came to €180 & €90 before postage😓.

A friend of mine recommended trying electrical contact cleaner and things called contact cleaners - basically minature nail files that allow you to file the contacts clean. And that's all that was wrong, the contacts had become tarnished and after I unplugged the washing machine and cleaned up ther terminals with the files the alarm disappeared and the dosing system works again.

I hope this helps someone, I've gotten a lot of help on here

cc77 · 19-12-2023 4:42pm

Ive had a broken drawer for a while and posted a few requests in the past to repair it, as only one of the pumps has stopped working. I had another look for solutions this week and found your post so thought I would ask a functional question to help me test.

Is there any chance you could measure the resistance between the various connection pins for me please?

I think the left most 3 (as in your picture) are for the metal sensor probes - with centre common - hence pin1-pin2 = probe 1 and pin2-pin3 = probe 2. Resistance as you would expect based on whether the metal probes are connected or not. pin1-pin3 is effectively open circuit unless both probes are connected.

Meanwhile the right 3 pins are for the pumps, however the resistance reads very strange for me - pin4-pin5 = 4.6Ohms, pin5-pin6 = 2Ohms, and pin4-pin6 = 6.6Ohms. I would have expected one of these to be open circuit (i.e. two independent pumps).

Thanks so much in advance!

renis · 21-01-2024 11:19pm

Hi,

I have the same problem with my Bosch washing machine. Just wonder if you have the same washing machine behaviour. The problem is that the machine does not use a detergent from the container and after every washing cycle an error E:00 is displayed (when iDos is selected to 1, 2 or 3; when it is off, there is no error). Performed self test with P:02 and an error E:10 was displayed. On the internet I found that this error means - iDos dispenser error. Seems that both pumps are not activated during the washing cycle. Initially I thought that there is a controller problem, so I removed IDos controller and checked if any relay (there are two relays, one for each pump) is activated during the P:02 test. When the first relay is activated, immediately an error E:10 comes out. Seems that the pump does not operate and the computer terminates the test with the error. As I understand pump is powered by 7V???, because one leg of relay is always on power 7V. It is not easy to rotate the cogwheel, so in my understanding 7V may not be enough... Anyway, to bypass the relay, I shortened both pins on the relay, but the pump was not activated... So, I checked the resistance of each pump: pin4-pin5=2.4 Ohms, and pin5-pin6=1.8 Ohms. I would say it is almost the same as yours but not sure if it is normal. I will try to operate pumps directly from external power source.

The biggest problem is that I have no idea how to get inside these pumps :)

P.S. I tried with external source. Softener pump works perfectly, but main detergent pump barely spins. Seems it is full of sh*t. So, the problem is identified, but not solved :(

ikb42 · 25-01-2024 12:28am

Hi, did anyone work out how to get at these pumps yet?

cc77 · 27-01-2024 5:51pm

Sadly I have used the one pump that is working and cut a groove in the tray so it all acts as a single reservoir now, but when the second pump dies I'm definitely pulling it apart.

If anybody has one that's totally dead and able to disassemble I'd love to know the steps, or help disassemble remotely! I still can't understand the resistances as if expect it to be symmetrical and both pumps are the same...

Gut feel says this is glued for water ingress protection, but I'd love to be wrong ....

cc77 · 27-01-2024 5:58pm

https://www.boards.ie/discussion/comment/121651774#Comment_121651774

Those resistances are definitely more even than mine given they are similar to 2ohms each (though with a huge variation which is surprising). Given they are attempting to dose detergent I'd expect them to have very exact resistances to be accurate flow control...

renis · 31-01-2024 8:49pm

I managed to completely disassemble the pumps :) The pumps are not glued to the dispenser, only three clips hold the pump case. But the problem is that the pump motor wiring is very short. The easiest way to remove the pumps was to remove the dispenser cover. But IT IS GLUED, so I had to rip off the cover and untie the wires.

Once the pumps are removed, the pumps themselves can be disassembled. In my case, the softener pump (pin 4 and 5) works fine. But the dispenser pump did not work. I disassembled and cleaned everything inside the motor (carbon brushes and rotor contacts). After such a procedure, the pump started working, but still imperfectly.

I assembled everything in the reverse order (glued the lid of the dispenser). It works now, but the dispenser pump still gets stuck sometimes. I'll take it out again and probably replace the pumps since we don't use the softener that often.

If someone finds a shop to buy the motor itself, it would be great if you let me know :)

alecia · 20-02-2024 1:01am

I found this thread because I'm having a similar problem with my Bosch serie 8 - the idos fabric softener doesn't seem to be working. I've taken the draw out, drained the compartment, cleaned the pumps, done a drum wash and even watered down the softener to a thinner consistency. In trying to do a thorough clean and remove any clogs I've realised I actually can't figure out where the softener is drawn up from and dispensed into the machine? Is the the gap/hole in the lid as pictured below? Through the small hole near the pump? And then it drops down get mixed with the water and sent into the drum?

The detergent seems to be working so I don't want to take apart the pumps just yet in case..

azimuth_pl · 14-09-2024 9:52am

Hi All, I have found this thread extremely useful in determining the rootcause of my iDOS not working.

I'd like to share some pictures that might help in dismantling the tray.

The top of the tray is ultrasonically welded to the bottom what causes the plastic to melt and glue both parts together. This proves that this was designed not to be dismantled but it can be done without much if any damage.

I used a blunt knife (a wristwatch caseback opener knife to be exact) because I wanted to tear the two layers apart and not cut into the plastic or wires and accidentally damage more than intended.

I used the knife like a chisel starting from the most visible gap next to the blue connector and hammered the side of the knife pushing downward at every step along the seams. You can clearly see where the welds are by checking how light reflects on the surface of the plastic. Once I reached the bottom where there is a bigger and deeper seam I used a longer kitchen knife.

After opening the tray you can unclick the blue connector plug and loosen the wires.

I found removing the motors the most challenging as each is held with three clicks that require a dedicated tool or a lot of wiggling and some minor damage to the plastics to get the correct leverage and unclick the motors.

My motors were completely rotten away and the previous owner must have been soaking the tray in water for long periods of time. I just can't understand how water got inside and rusted everything inside out.

Fortunately, despite the poor state, one motor for the softener does work so in the interim I can resolder it in place of the washing liquid motor.

My motors are branded as Johnson but I'll search Aliexpress or eBay for a suitable size DC motor. These are most likely variable 6-12V and are not very sophisticated. Finding the right diameter and length should be fairly easy and they sell roughly for $10 per piece. I connected a 9V battery and my motor spinned without issues. The optimal voltage might be 6-7V but a slightly higher voltage won't do any harm considering they are variable till 12V.

btw. pins 1-2-3 on the blue plug are for liquid levels so a multimeter will always show an open circuit unless you short the corresponding prongs that dip into the liquids.

pins 3-4-5-6 will run the motors.

Bosch i-dos -- fixing the detergent drawer

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