One day, early in the summer, I hit the A/C switch and the security light came on, followed by the battery symbol and the trunk open warning. I pulled over and shut the car off. I tried to restart it thinking it would reset something. Instead, when I turned the key to the full start position, everything goes black, like the result of a direct short. The headlights, heater blower, instrument panel lights, etc. All instantly cut. When I release the key to the normal run position, ta-da they all come back on! It seemed like an ignition problem to me, so I pulled the ignition relay and traded it with the A/C relay, as they were identical. The car started and ran great! Over the next couple of months, it happened more frequently, with more warning symbols including a high beam out warning (which wasn’t true). The door locks will engage and disengage on their own, the trunk opening on its own (then warning me that the trunk is open), the horn would begin to honk on its own. It did all these things while the car was running. (It decided to perform its horn trick at the funeral of my wife’s mother, much to my embarrassment!) Once the car was turned off, it would refuse to start. As the symptoms progressed, I found that many times I could get it to start again by tapping on the relay blocks under the hood. Most recently, I was about 10 miles from home and started my car. It started like normal but security light, battery light, high beam out warnings were lit up. Judging from my recent experiences, instead of shutting it off and banging on the relays, I shot for home. I figured I had at least 10 miles left on the battery if the system wasn’t charging it. It was still running perfectly when I pulled in my driveway, despite all the warnings. I turned the car off, then tried to start it again. All the familiar warnings were there and I had the same symptoms as described earlier. After banging on relays, trying many voodoo tricks and dances and the “10-minute trick” 3 times, now only the battery and the security warnings are displayed. (It did change how they are displayed, however. Before, it would flash the battery light one time, followed by the security light three times. After the 10-min trick, it displayed the battery light one time, followed by the security light one time. However, as soon as I attempted to start it, it returned to its previous pattern of one battery flash to 3 security flashes.) When I turn the key forward, the starter will not engage and I am back to the loss of all dash lights, blower and headlights, etc. For what It’s worth, I can hear the fuel pump kick on when the key is first turned forward, so it isn’t a fuel pump issue. I have unhooked the battery, given it a full charge, and returned it, nothing. From what I have read, I suspect a VATS or BCM problem.
Since then I replaced the battery, same result. I put diodes on the passlock wire. Cleaned all the contacts in the ignition switch with sandpaper. Tried the “10-minute trick” still nothing. I got the engine to crank by breaking open the crank relay and pushing the contacts together. It ran for 3 seconds and theft lock shut down the fuel pump. I can repeat this starting trick as many times as I want, but the passlock always shuts down the fuel pump, thus making the car stall due to lack of fuel. The fuel pump relay I believe has 2 functions one to apply pressure to initially start the car, runs for 3 secs and the then the second set of prongs take over the fuel regulation to keep the vehicle running.
Why can’t I install a manual switch to power the second set by hooking directly to B+? I have been trying the “10-min trick” since October without success. Each time I change anything, I try the trick again. Still no success.
Also, is my no crank situation with the key due to passlock problem?
Monday, December 9th, 2019 AT 12:13 PM
(Merged)
