Dell 2135cn Service Manual page 720

Chapter 3 Removal and Replacement Procedures (RRPs)
Replacement 39 SWITCH (PL5.1.9)
1) Engage the connecter (P/J291) of the
SWITCH.
2) Attach the SWITCH to the printer,
secure the SWITCH with the two hooks.
Go to the next replacement step:
Replacement 42 COVER TOP (PL10.1.4)
3 - 218
Version 
2008.02.01