Installing an aftermarket pressure shut-off switch in the closing assist pump
Here is one of the most ambitious repairs to the closing assist pump that I have had the pleasure of posting here. I corresponded recently with Christian (looks like he is from Sweden by email address) who was going to attempt to install an aftermarket pressure shut-off switch in his closing assist pump whose original switch was unrepairable (I’m not sure why at this time.). I just received a success story by email yesterday.
Christian found a switch from
Farnell / Electronic Component Distributors / Suppliers / Electronics, Electrical Parts, Electrical Components and Wholesale Electronics., part number 6101-0018, manufactured by Herga.
Farnell Export
This switch operates at pressures from 0.025-2.75 bar (1-40 psi). There are 4 different springs that come with the switch so that you can choose the correct operating pressure for your application. The closing assist pump is supposed to reach pressures greater than 2 bar during normal operation, and Christian reports the proper spring to use is the one in the yellow bag labeled 13-0022-A-87.
The installation is pretty simple according to Christian’s pics. Here is a close-up pic of the new switch showing the contacts that are used.
First, you must desolder the old pressure shut-off switch from the circuit board, and disconnect the air line to the switch. See pics in earlier sections. There are only two actual electrical connections, but there are three solder connections. The third solder connection doesn’t connect to anything electrically. I guess it’s just there to help hold the switch to the board.
Now, solder two wires that will go to the new switch to the electrical contacts on the board.
Solder the two wires to the switch contacts shown, and using about 10 mm or less of a flexible plastic hose with 4 mm ID, connect the new switch to the air manifold.
Before you put the pump back together, you need to adjust the pressure shut-off properly. So, using the trunk or any door, do a test closing run, and time the operation of the pump as described earlier. There is a screw on the switch to adjust the shut-off pressure. Adjust the switch until the pump run time after the door or trunk has latched is about 2-3 seconds.
That’s it. The rest of the job is packaging the switch properly in the area where the original switch resided. Be careful not to pinch or kink the air line. In the two following pics, you can see that Christian used wire ties to hold the switch in place and secure the air hose.
Cheers,
Brett