Final Check on the MGB Wiring Harness - Almost There!

We’re wrapping up the 1980 MGB wiring harness install today. It’s time to check out each circuit to be sure that everything is working as it should. Before we get started, we’ll discuss how to hook up the new radio and USB port so that we aren’t overloading the wiring. Then, with our battery test fuse in place, we’ll start in the cockpit checking the gauges, dash lights, marker, headlights, map and boot lights. We had a few minor hiccups that we show you how to easily fix. Once we know that all of those are working as expected, it’s time to finally turn the key…but only to the on position, it’s not quite time to try to start it yet. So we then can move on to test the wipers, the blower fan, turn signals and hazards where we again find a small issue. Then we check the new radio, USB port, discuss the testing procedure for the fuel gauge, and find out why the back up lights aren’t both working. Last to check at this point is the washer pump and we share some advice that may keep you from having to replace it. After removing our test fuse at the battery, only then do we turn the key to start…and nothing happens. So it’s time to diagnose again and with a quick fix and hooking the fuel pump up, it roars back to life. But troubleshooting isn’t quit done yet. We listen for the anti-run on solenoid then go back in the cockpit to check on the tach, and other gauges and discuss the reason why your gauges may be reading high. We need to get some heat into the engine to check the temperature gauge and to be sure the fans are coming on and turning off at the correct temperatures. After finding the temperature gauge is still not working, we discuss the differences in the temperature sending units between pre, and post ‘77 cars, and how to test them. Before we’re done, on these late B’s there is one wire we want to leave disconnected, watch to find out why. Now that we have tested everything, only then is it time to finish carefully mounting the dashboard and neatly tying up the wires, it’s very important to take your time on these last steps because it could be the difference between a successful install and melting down your brand new harness.


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