1998 c230 trunk release problem
I have a 1998 c230 sedan with a remote trunk release problem. I have tried some diagnostics listed below but cannot get the system to work properly.
The trunk release works first thing in the morning with the remote when the red light on the center console trunk release button is not lit. Once the doors are unlocked the trunk release button on the center console lights up red. Then the problem starts. I can get into the trunk with the metal key, but it now will not work from the release button in the center console and the remote key will not operate the trunk release.
I think what is going on, the car thinks the trunk is open ( the red light on the release switch in the center console ) and will not let the remote or center console switch work. I have tried to replace the Vacuum pump assembly with a used one with no luck. I have also tried to look into the trunk closed sensing switch at the trunk latching assembly. I have tried to test the sensing switch with no luck. There is no difference in ohms readings between an open and closed trunk latching assembly. Both positions give me an infinite ohms reading. Looking over a Mitchell electrical wiring diagram and the trunk closed sensing switch looks like a grounding type of switch. ( yellow wire into the switch and solid brown wire out to ground ) I have tried to short the two wires at the switch with no luck. I have left the wires to the sensor disconnected and the system did not work. The red light stays on. I have tested the wire from the vacuum pump to the trunk latching assembly and the yellow wire tests good. The grounding wire at the other end of the switch tests good also. I have tried to both ground and infinite ohms the yellow sensing wire from the vacuum pump bypassing the wiring that bends when the trunk opens and closes with no luck. I am unsure of what to try next? I think the trunk closed sensor switch is bad but I am unsure if there is something wrong with the center console switch because I cannot get the system to work by manually connecting the sensing to the tow different conditions that the wiring diagram says is should see?
One other funny thing it does is that if the red light in the center console is off and the door locks are open the trunk remote will not work and the red light will be lit after trying! Not sure why this happens
Does anyone have any experience with this system and knows what to try next? Thanks John
PS the trunk wiring has given me problems in the past. The car used to arm the alarm sometimes when closing the drivers door. The problem was fixed by cutting the black wire that connects the the locking pump to the trunk locking sensor. I think the wire was grounding itself somehow when the drivers door was closed. Once the black wire is grounded the car thought the car was locked from the trunk and is should set the alarm is my best guess as to why this solved the problem.
|