intermittent problem
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
intermittent problem
I own a 1984 Corvette. Sometimes when I open the doors the interior lights do not go on. And then I cannot open the rear hatch with the switches. I can turn the lights on and off by pressing the light switch on the door. So if the lights have power but do not go on when I open the doors, both sides where do I look.
Thank you
Thank you
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
door ajar switches fail mechanically and/or electrically
jseremba,
if by 'light switch on the door' you mean the 'door ajar' switch which is mounted into the door, has a plunger and when the door is closed it is depressed inward by the door jam,
then that switch is exactly your problem
These switches, when popped-out (door open) close a circuit which the CCM uses to both turn on the interior lights and enable the hatch switch.
These switches either sticks and do not pop all the way out when door is open (only use Vaseline, other products swell the plastic), or fail to close/ground the circuit electrically when the switch pops all the way out.
The CCM also has a diagnostic mode which would allow you to verify the operation of these switches (check FFM under CCM).
Good news, the switches are inexpensive and available via the Dealer/ forum sponsors/NAPA.
Also, the switches can be replaced right through their hole with OUT having to take the door apart (see FFM).
if by 'light switch on the door' you mean the 'door ajar' switch which is mounted into the door, has a plunger and when the door is closed it is depressed inward by the door jam,
then that switch is exactly your problem
These switches, when popped-out (door open) close a circuit which the CCM uses to both turn on the interior lights and enable the hatch switch.
These switches either sticks and do not pop all the way out when door is open (only use Vaseline, other products swell the plastic), or fail to close/ground the circuit electrically when the switch pops all the way out.
The CCM also has a diagnostic mode which would allow you to verify the operation of these switches (check FFM under CCM).
Good news, the switches are inexpensive and available via the Dealer/ forum sponsors/NAPA.
Also, the switches can be replaced right through their hole with OUT having to take the door apart (see FFM).
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
intermittent
jseremba,
if by 'light switch on the door' you mean the 'door ajar' switch which is mounted into the door, has a plunger and when the door is closed it is depressed inward by the door jam,
then that switch is exactly your problem
These switches, when popped-out (door open) close a circuit which the CCM uses to both turn on the interior lights and enable the hatch switch.
These switches either sticks and do not pop all the way out when door is open (only use Vaseline, other products swell the plastic), or fail to close/ground the circuit electrically when the switch pops all the way out.
The CCM also has a diagnostic mode which would allow you to verify the operation of these switches (check FFM under CCM).
Good news, the switches are inexpensive and available via the Dealer/ forum sponsors/NAPA.
Also, the switches can be replaced right through their hole with OUT having to take the door apart (see FFM).
if by 'light switch on the door' you mean the 'door ajar' switch which is mounted into the door, has a plunger and when the door is closed it is depressed inward by the door jam,
then that switch is exactly your problem
These switches, when popped-out (door open) close a circuit which the CCM uses to both turn on the interior lights and enable the hatch switch.
These switches either sticks and do not pop all the way out when door is open (only use Vaseline, other products swell the plastic), or fail to close/ground the circuit electrically when the switch pops all the way out.
The CCM also has a diagnostic mode which would allow you to verify the operation of these switches (check FFM under CCM).
Good news, the switches are inexpensive and available via the Dealer/ forum sponsors/NAPA.
Also, the switches can be replaced right through their hole with OUT having to take the door apart (see FFM).
today I pressed the light switch in the door jam so that the interior lights would be off and was able to press the door mounted hatch switch and open the hatch.
When I open the door and the interior lights do not come on I can still turn them on by pressing them.
I will check out the manual and look at the ccm diagnostic mode. Thank you. It just seemed peculiar that I could turn on the lights but they would not come on.
Thanks again
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I don't know the details of the '84 hatch release system. I have a diagram for a 1984 manual trans but not for an automatic trans. The weird thing (to me) is that it's tied in to the BRAKE light on the DIC. That light has to be on to release the hatch. There are two ways to release the hatch: 1) Put on the parking brake. 2) The weird part is that it appears that you can release the hatch when the ignition switch is in the START position (that lights the BRAKE light as part of the lamp test function).
I think that the auto trans requires that the trans be in Park or Neutral (my car does).
Last edited by Cliff Harris; Apr 7, 2014 at 02:24 AM.
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
There is no CCM in an '84. That didn't come until the '90s (I don't know exactly when -- probably with the LT1s).
I don't know the details of the '84 hatch release system. I have a diagram for a 1984 manual trans but not for an automatic trans. The weird thing (to me) is that it's tied in to the BRAKE light on the DIC. That light has to be on to release the hatch. There are two ways to release the hatch: 1) Put on the parking brake. 2) The weird part is that it appears that you can release the hatch when the ignition switch is in the START position (that lights the BRAKE light as part of the lamp test function).
I think that the auto trans requires that the trans be in Park or Neutral (my car does).
I don't know the details of the '84 hatch release system. I have a diagram for a 1984 manual trans but not for an automatic trans. The weird thing (to me) is that it's tied in to the BRAKE light on the DIC. That light has to be on to release the hatch. There are two ways to release the hatch: 1) Put on the parking brake. 2) The weird part is that it appears that you can release the hatch when the ignition switch is in the START position (that lights the BRAKE light as part of the lamp test function).
I think that the auto trans requires that the trans be in Park or Neutral (my car does).
the car is a 4plus 3 manual transmission. Sorry but what does DIC stand for. Thank you for the help
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
..WW.
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Last edited by WW7; Apr 7, 2014 at 06:07 AM.
