Electrical Relays and relay updates

One of the easiest items of preventive maintenance that owners can perform on their DeLorean is to install one of DMC's Replacement PN K111168 or Improved PN K111168A relay update kits. 
These kits replace all of the old changeover relays, the Lambda [aka RPM or main fuel] relay, the three circuit breakers, all fuses and a jumper to take the place of the fan fail module. The only difference in the kits is that the "Improved" kit replaces all the changeover relays with new Bosch units, while the replacement kit uses NOS relays from the DMC inventory. We recommend replacing the NOS relays every few years, whereas the Bosch relays should be good for a long time. 
The new circuit breakers replace the old 25A PN 106085 breakers used for the cabin fan and door lock circuits, and substitute a new 40A breaker PN 106086 for the old 35A radiator fan circuit. This last replacement will stop any unexplained cooling fan cycling.  
A fused y-style jumper PN 111122 replaces the blue fan fail module. The module is notorious for failing under load and disabling the cooling fans, without any indication of failure. Its function was marginally desirable anyway. The factory replaced the module with an unfused jumper in September of 1982. The presence of the blue module in the relay compartment is a strong clue that a relay update kit is needed.
Finally an NOS Lambda/RPM relay PN 101064 (aka fuel pump relay) replaces the old original in both kits - keep your working original as a spare in the glovebox.
CAUTION: When replacing the relays, it's common to have terminals push out of the bottom of the socket. If, after replacing all the relays you find an operational problem, the first thing to do is pull out the suspected relay and inspect the socket to make sure that the metal terminal blade is in the correct position. For example, if the low beam headlights don't work after doing the work, pull out relay #1 in the illustration below for inspection. If the terminal is pushed out, you will need to lift up the relay bank (held in place by one screw), re-form the barb on the terminal, and snap it back in to place in the plastic socket. 
Additionally, a complete set of fuses is included. Inspect the fuse box for melted terminals and repair or replace as needed. Installation instructions are included along with the following "quick reference" label for handy future reference. 
We recommend cleaning or replacing the fuses at least once a year to prevent heat buildup and possible melting in the fuse box as a result of oxidized fuse terminals. Refer to the Fuse Box article for details. 
Written by Warren Wallingford with edits by James Espey, DeLorean Motor Company (Texas)
Revised 1/13/2022 ET (formatting and links)