Jonny Retrofit Posted January 15, 2024 Posted January 15, 2024 Troubleshooting All Classic Retrofit fuse panels are electrically tested before shipping. With over a thousand installations we know that there are no faults with the design of our product and that manufacturing issues are few and far between. Relays are high quality and rated 100,000 cycles. Miswiring The most likely source of problems will be failure to connect the wires as per original. It is easy to miss a wire on the bottom row as they are hard to see. It is also easy to forget to skip a gap as not all terminals are occupied on the bottom row. Refer back to your reference photos and see if you can spot a mistake. 'Out by one position' miswires result in odd behaviour (e.g. one headlamp and one side lamp instead of two headlamps) or even failure to start. Do not add external links for headlamps, this can make the headlights stay on when the ignition is turned off. Keep to factory wiring - it will work! 'Foreign' wires The second most common cause of odd behaviour is likely to be the hornet's nest effect. That is, you've been fiddling around with wires that haven't been moved in many years. Perhaps you have found or disturbed 'mystery' wires. Over the years, your car has met a few auto electricians for stereo, alarm and other accessory installations. It isn't surprising to find that there are odd wires, splices and -horror- 'scotch locks' in the wiring loom. Identifying rogue wires is actually pretty easy. All the original Porsche wires that terminate at the fuse panel have ferrules (small crimps) on the copper part of the wire. If the wire does not have this it is either a 'foreign' wire or an original wire that has been cut. It is good to trace these wires and see if they are actually doing anything. Remove if not. No Headlamps, no relay click? Grounding: If you cannot hear the relays click when you turn the lights on, it is almost certainly due to bad grounding. The headlamp relays use the mounting screw to the left of the relays as a ground. You must attach the panel to the car with the screws or the headlamps will not work. It is important that the screw has good electrical contact with the new fuse panel and is properly secured into the metalwork behind. The black metal panel itself should be grounded to the chassis via the top wing/fender screws. If you have a meter then the you should be able to 'buzz' (test continuity) between the mounting screw and chassis (disconnect battery first). If the metalwork or the car has been repainted, sometimes the electrical connection is not made at the wing/fender screws. There are two ways to remedy this: 1) Loosen the wing/fender screw and take the paint back to bare metal beneath it. 2) Try adding a extra ground wire to the black metal bracket. The most convenient point to do this is on the far left of the metal bracket. There is a mounting screw and just to the left on the inner wing is an earthing stud. Connect the two points shown in green on the picture with a wire of at least 1.5 mm2:
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