Q – My 96 Twin Turbo had a number of strange symptoms this spring. First the battery was dead but then, after I got is started, the power locks would not work. If I push the lock button it would act as if they locked but then they instantly unlock. The key would also not work to lock the car. And at random, the parking brake warning light comes on even if when the lever is down. Sometimes I could force the lever down further and the light would go back on a few miles later. The light would also come on when the turbo boosted. Another oddity was the dashboard lights. At night, they surge brighter and dimmer at random. It is like the car is possessed! Chuck
A – I wonder if you jumped the car, then disconnected the cables and ran the car with a dead battery? Yes it will run with a dead battery but the alternator will also freak out…And not in that fun Frank Zappa way. The alternator can sent a power surge to the electronics and cause all manner of corruption and chaos! You don’t want that, so I hope you did not do the deed.
Let’s tackle the door locks first. In the doors, the actuators which are electronically controlled servos, move the mechanical lock rods up and down. They can sometimes get corroded and when they do, your power locks get confused. Once you take the door panels off, the actuators can be disconnected to determine if it is a mechanical or an electronic problem. You should then be able to manually lock and unlock you car temporarily. But I bet you will find the problem in the connections or the wiring if you did not fry the module when you jump started your car.
The parking brake warning is another fairly simple circuit that gets complicated when the signal is sent into the “multi function instrument” where all the warning lights reside. If you are lucky, when the console is taken apart, you will find a paper clip, an ink pen, a few coins or other debris that fell through the whiskers intended to keep crap out of the console. If not, the circuit board in the “MFI” can develop cold solder joints and get a bit kinky in its old age. In that situation, a qualified instrument repair shop such as Specmo, conveniently located in Burton, Michigan can inspect, re-solder, and do their voodoo on the unit and maybe your problems will go away. (they offer no guarantee on this work)
But always start by cleaning out the debris first.
The pulsing instrument lights may well but due to damage caused by a faulty voltage regulator or wiring issues. On this model, a ground fault or voltage drops caused by overcharging can cause this symptom and only testing and time will tell if there is a real problem or just an idiosyncratic light show. Stay tuned. MC