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the new battery in my car goes dead in about 5-6 days of non use. I isolated the drain to the 5 amp fuse that controls the radio (both head and amplifier) and the security system. I had the radio checked and replaced the amp so I am pretty sure it is the security system issue. As you all know that was a BS system from the start which engaged when you and the fob walked away from the car. It never worked right and I removed the batteries from the fobs to stop it from doing that. Now it seem to be drawing amps when the car is dormant. How can I stop it from getting power? If I pull the fuse, I lose the radio!

I also noticed for the first time that when I connect the battery cable (and disconnect it over and over) both headlamp motors pulse (make a noise). Headlamps work fine in every way, just wondering what the initial pulse is and if it is normal to do that.
Thanks, Bob Smith
 

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Find the security module and unplug it.

There is a solid state headlight motor module.
A pair I recall.
Normal what you desribed.
 

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Discussion Starter #3
Find the security module and unplug it.

There is a solid state headlight motor module.
A pair I recall.
Normal what you desribed.
Thanks so much for the insight. Now trying to find that module will be fun. I don't have a schematic. The good news is that there IS a module to control it, had my doubts.
 

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Thanks so much for the insight. Now trying to find that module will be fun. I don't have a schematic. The good news is that there IS a module to control it, had my doubts.
Before you get too carried away with the electrical on your headlight issue, If you hear the gears in the motor skipping it is because the big plastic gear in the motor is stripped. The module sends power one way or the other. period. There is a spring loaded switch inside the motor attached to the worm gear. When the headlight door hits a stop the bind operates the switch and breaks the power circuit. Your gear is stripped and skipping instead of pushing the worm gear and breaking the circuit. Or the 3 nylon bushings have disintegrated. Either way, The repair is a bronze replacement gear. You can get it here: https://www.ecklerscorvette.com/corvette-headlight-motor-repair-kit-1988-1996.html

If both doors are affected only do 1 at a time so you can look at the other side going back together. just search on eckler's for your year c4 headlight motor repair kit. Because it is that common that there is a specific repair kit just for this issue.
 

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Discussion Starter #5
Before you get too carried away with the electrical on your headlight issue, If you hear the gears in the motor skipping it is because the big plastic gear in the motor is stripped. The module sends power one way or the other. period. There is a spring loaded switch inside the motor attached to the worm gear. When the headlight door hits a stop the bind operates the switch and breaks the power circuit. Your gear is stripped and skipping instead of pushing the worm gear and breaking the circuit. Or the 3 nylon bushings have disintegrated. Either way, The repair is a bronze replacement gear. You can get it here: https://www.ecklerscorvette.com/corvette-headlight-motor-repair-kit-1988-1996.html

If both doors are affected only do 1 at a time so you can look at the other side going back together. just search on eckler's for your year c4 headlight motor repair kit. Because it is that common that there is a specific repair kit just for this issue.
Thanks for all that headlamp info. They both work fine however, up/down stop and go. No noise or gears skipping. My only concern is that when I connect/disconnect the battery cable they both 'pulse' No movement of any kind just make a sound very much like a relay. Nothing is wrong with them mechanically, I just never heard it before and wondered if it is normal for them to pulse when first energized like that?
Now I have to locate the security module to unplug that thing
 

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Thers a **** load of vids on u-tube,that's for a 85 since it mentions the cold start inj. The inj was done away with on 86 & ECM controlled after that.What year is your vette ?
 

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Discussion Starter #8
I am hard pressed to believe that the VATS system is causing a low amp drain when the car is just sitting, or that I should eliminate that system to cure it. Seems like something is shorted or defective drawing power when it should not be doing so. The fuse for both the radio head and amplifier AND "security system" (as described in my manual) is a 5 AMP. When I pull that fuse the battery drain stops, but I have no radio?????

UGH, my 60 Impala did not have these problems!
 

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I guess I'm not savvy enough to get what they are telling me as a resolution to my problem Something is sucking power when the car is off and dormant. That resolution would remove the VATS system entirely and I thank you for the link. I'm still pressed to understand what is pulling voltage in that system. It works fine and the car starts (when the battery is charged) and runs just fine. Let it sit for 5 days and dead. I'm missing something here?
 

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I guess I'm not savvy enough to get what they are telling me as a resolution to my problem Something is sucking power when the car is off and dormant. That resolution would remove the VATS system entirely and I thank you for the link. I'm still pressed to understand what is pulling voltage in that system. It works fine and the car starts (when the battery is charged) and runs just fine. Let it sit for 5 days and dead. I'm missing something here?

What you are missing is that the vats module is likely not going to sleep. This can happen from a few reasons. First and foremost there is a set of contacts in the ignition switch lock and tumbler that make up the "key in" circuit. These pins get jumped to each other when you slide the key in the ignition. If these pins stay connected then even after you and the key have left the car, the car still thinks the key is in the ignition. This is one of a multitude of possibilities as to what is causing your specific symptom.


Another possibility is the ccm itself has failed and the board inside or some of its components have fried or gone short. But without this module or the 5v square wave signal it sends to the ecu, the car will not start. Hence why you will need a bypass. Because the ecu is looking for permission to start and that permission comes from the ccm in the form of a 5v signal at a specific frequency. There is a factory correct way to delete the vats without an aftermarket module. This method will involve tunercats and reflashing your eeprom and deleting vats from the ecu so it no longer looks for this permission before starting.


I have personally observed common c4 battery draws to be in doors where the courtesy light right above the inside door handle gets hot and melts the housing or when the door cards are removed and replaced poorly and these wires get pinched and ultimately short to ground. I have also observed a weird draw on a few c4's to be under the center arm rest. There is a connector, I believe a 4 pin connector with what looks to be a diode connecting I believe pins 1 and 4 and this diode fails and becomes a short to ground for power.

Both of the above mentioned sources for a draw come seemingly from the courtesy light circuit. But I would just like to point out that the courtesy lights are one of the things controlled by the ccm. Good luck. From what I have read here so far, the best thing you can do from here is find an electronic specialist with experience chasing gremlins in c4's. I am in South Florida.
 

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Discussion Starter #13
Maniacmachanic1: Thanks for a very comprehensive explanation of what this might be. Can I presume that the 5 amp fuse for the radio and security system is powering all that and is the reason why the drain stops when I pull that fuse? Secondly I need your address as I now have to come visit you for the fix: laughing:
If it were a courtesy lamp issue why would pulling the radio/security fuse stop the bleeding? As a test of the ignition issue you related could I leave a key in the ignition (off) and wait a couple of days to see if the battery is drained?

Thanks again for all this.
 

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could a bad ground be doing this? I read that somewhere a while ago. If yes I guess you just go after all of them but not sure how that could drain the battery
 

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could a bad ground be doing this? I read that somewhere a while ago. If yes I guess you just go after all of them but not sure how that could drain the battery

Well have you unplugged both parts of the radio? How do you know the draw isn't coming from the radio? The radio control head is what you interact with and surely you know right where that is, however the radio receiver box is in the right rear storage compartment and it too gets powered by the same 5 amp fuse that is supplying your draw. And by the way, I would like to know exactly how severe your draw is. This will require an ammeter connected in line between battery ground and the car's gnd cable.
 

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Maniacmachanic1: Thanks for a very comprehensive explanation of what this might be. Can I presume that the 5 amp fuse for the radio and security system is powering all that and is the reason why the drain stops when I pull that fuse? Secondly I need your address as I now have to come visit you for the fix: laughing:
If it were a courtesy lamp issue why would pulling the radio/security fuse stop the bleeding? As a test of the ignition issue you related could I leave a key in the ignition (off) and wait a couple of days to see if the battery is drained?

Thanks again for all this.
 

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To Margaret Behr: Hi Peggy, good to have you with us
 
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