Hey guys, I have a bad blower regulator box, mine has a number 1 147 328 027
I have been looking on line and have found what seems to be the same part with different numbers most ended in 026 . Is there a difference? Don't want to fry something.

Yes, they are different.

The temperature regulator number 1 147 328 027 is in the Bosch part number 1-3-3-3 spacing format.
The Mercedes part number should be located below the Bosch number.
The 10 digit MB part number will be preceded by the MB star and the 10 digits will usually in the 3-3-2-2 spacing format (Example: 123 456 78 90).

Assuming the part is original, you want to replace it with the same part number
(or an updated replacement part that is confirmed by the dealer as being interchangeable with the original part).

If you contact the dealer (or classic center) they can conduct a VIN based part search.
They can provide you the correct MB part number and pricing for the temperature regulator for your vehicle.
Apparently, the online dealership part catalogs now only go back to 1984 for parts searches.
I couldn't find the MB part number for your vehicle in my search.

If NLA or too pricey, you can buy a used unit online or pull from a donor/junkyard vehicle.



Add a 1 amp fuse inline to your auxillary water pump power supply to protect
your CCU from getting burnt traces when the auxillary water pump siezes up.

Or remove/unplug the auxullary water pump...you can probably do without the
slightly increased heater output at idle that the auxillary water pump provides.

__________________
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Thanks Alec, this car although running well has had some weird problems. Continue to find that whoever worked on it prior took many shortcuts. I have already replaced the aux. water pump , and climate controller . I rebuilt the mono valve along with fixing some misc backyard repairs allegedly done by qualified shops. Little by little she will be tightened up. She now runs well ,shuts off correctly and shifts well. Just need her to be comfortable to drive in the hot weather.