WIRING ISSUES

1 Attaching a direct earth to the bulb holder on the Saab’s non-functioning offside front indicator had the bulb flashing as a temporary fix. As the headlight on that side of the car was also very dim and the electric radiator failed to cut in all the time, we needed to urgently locate and check all the earth connections. 2 To ensure the cooling fan worked properly, we connected a temporary earth between the negative connector on the temperature sensor at the top of the radiator and the chassis. Shorting the two connectors out on the sensor fired up the fan, which proved the problem was down to bad earth. 3 Further investigation showed how the three way connector for the Saab’s errant H4 headlight bulb was starting to distort, another sign that a bad earth was causing the light to dim. Main beam was also dim, so the next job was to locate where the main earth point for the headlight was located in the engine bay. 4 While investigating the non-working front indicator, we noticed the side repeater wasn’t working and the reason for this was found to be down to a missing bulb holder rather than a bad earth. Sourcing a second-hand light unit from Saab specialists Volsaa Engineering cured this annoying problem. 5 Testing the original earth leading to the fan sensor at the top of the radiator with a circuit tester confirmed the intermittent fault with the fan was definitely down to a bad earth. These testers really handy and can quickly locate an open circuit, so it didn’t take too long before we found a large bunch of broken and corroded earth wires. 6 The battery on the Saab 900 earths out on the cross member located beneath the radiator and is shared with a cluster of earths from the headlights, front sidelights, indicators, horn, radiator cooling fan and gearbox. All the small wires had broken off and the head on the bolt was knackered, making removal with a normal socket impossible.

7 To remove the rounded off bolt, the technicians at Volsaa Engineering used a special socket that tightly gripped the damaged head as it was wound out. Once the bolt had been removed, the full extent of the damage could be seen and only a couple of the small black earth wires remained in the circular connector– no wonder half the Saab’s electrics were on the blink. 8 While reconnecting all the loose wires from underneath the car, the main feed to the radiator cooling fan snapped where it entered a multi-plug. After fitting a new crimped on connector, the loose wire was replaced but this quick fix would come home to bite us when we took the car over to Belgium – more on that next time! 9 Grouping all the small black earth wires into the original big connector would have required soldering them in place but as there wasn’t enough space to get a soldering iron and two hands into the limited space with the radiator installed, so we opted to use several smaller crimped connectors instead. 10 This shows how badly knurled the earth bolt was and the state of the old three-way connector for the Saab’s H4 headlight bulb. A new bulb connector was grafted into the wiring loom and the broken connector on the right hand side of the image was the one that had held all the small black wires.