OCTOBER 2023 AFTERMARKET 29 several fuses. Locations; SB7 and SB8; SB28 through SB31. SB7/SB8 are both powered from the Simos (PCM) current supply relay J363, which in turn is supplied via J17 fuel pump relay. The J17 relay is controlled via an ignition pin, 15 positive, with ground via Simos pin 26. Please refer to Fig.1. So far, so good. We knew the PCM was not powered up and we knew the original suspect, the fuel pump, was also not working. My attention was then drawn to the correct function of the J17 / J363 relays. Anyone out there with experience of the relay panel on this 2011 model will know it leaves almost no access for relay removal let alone testing in situ. If you take a close look at Fig.2, which shows the power control module, you will notice I have cut out a large section of the lower dash panel which is covered from sight by the fuse panel cover. Game on! Both relays were fully functional when tested off-car. Steady on I now focused on the fuel pump relay control. The ignition supply pin 15 was present, but was also present on relay pin 31, which should be at ground to latch the relay. The ground was latched via Simos PCM pin 26. I stripped out the PCM and exposed the wiring armed with my trusty DMM check pin 26 which was positive. Please refer to Fig.3. So, I provided a temporary permanent ground. Please do not do this unless your confident in your knowledge of current flow schematics. Returning to the fuse panel, sb7/8/28/29/30/31 were now all live. The vehicle cranked and started promptly. So, the fault was a switched ground failure on pin 26. My time extended to five hours including gaining component access and modifying the dash panel, with a new PCM probably costing £900. You may recall I explained the fuel pump relay is latched from an ignition switched supply. If I provide a permanent ground to pin 26 the fault will be fixed, and the battery will not go flat as the relay is switched off with the ignition. I love jobs like this. I was getting almost giddy with the excitement. “Steady on” I said to myself, “there is still the passenger power window to fix!” Removing the door card and exposing the loom through the door aperture confirmed the wiring was in good condition, unlike what I found in the previous window repair. Obtaining the current schematics for the power control module, which was still exposed from the previous PCM repair, I quickly established no power supply to the window control module j387, theoretically via fuse 51/52, here we go again! Fuse 52 is N/S front but was not wired in the panel. Not fancying several hours more loom searching, I took the entire current flow schematics home, and sat quietly studying them. Sad really, however I did notice my vodka glass was always full! My new plan for the following morning involved strong coffee, and reversing the problem, conducting a continuity test from the window module power supply, working through all fuses rated at 25 amps. To my surprise there was a missing fuse location 25 with continuity to j387. When fused up at 25a, both windows now operated. The real lesson here may be this: Do not rely on what you expect without testing and, where necessary, go fishing. Of course, I will never find out the answer to the ultimate question from this job: Who took the fuse out and why? Fig. 1 Fig. 3 www.aftermarketonline.net Fig. 2
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