Anybody got any experiences with theft deterrent modules for the early C4's... specifically 85's? My security light always flashes with the ignition off... even with the doors closed. The security light goes out when the ignition switch is in the on position. What I'm looking for is what signals (high or low) are supposed to be on each pin with the ignition on and off.

Does anybody's TDM work? What makes it go off (85)? I think I remember that the driver key lock is supposed to reset it, arm, or disarm it. Anybody run their car with the TDM disconnected? Comments?

Thanks


[Modified by billreid1@home.com, 8:22 PM 10/9/2001]

 

Don't know anything about your problem, but if you need a new module, try Gene's Karshop.........karshop@msn.com or 863-816-0636, he has used Vette parts....... :yesnod:

 

with my 92 i must lock the doors with the electric locks (i.e. the switch and not the slider) to arm my stock anti-theft system. the security light goes from blink to steady on, and when i close the door the light goes off after a few seconds.

sorry i don't know specifics about your 85.


[Modified by tempest, 9:28 PM 10/9/2001]

 

my security light blinks with the doors open, but no key in. i installed a gm keyless entry directly up to my TDM, and when i press the unlock button, the security light flashes, and when i press lock, the light goes off. im guessing its supposed to stop flashing with the doors locked and closed, and blink with them unlocked and closed.

 

88L98,
Thats good info. Right now my security light blinks all the time... doors open or closed, locked or unlocked. It only goes out when ignition key is on. I opened up my TDM and found a blown transistor... replaced with a spare from my 84 parts car... same damn thing. Problem is something is running my battery down and I think its the TDM... takes about 2 weeks to kill the battery if I don't drive the car in that timeframe. Otherwise I don't really care if the light blinked when the car is off. I would like to get the factory system working correctly if possible. Right now I've got an email to Brian Thompson. I installed the GM VKE 1000 keyless entry system on my 85. Anybody can access his VERY informative website at http://batee.cc.umr.edu/corvette/ . Many of the signal wires hook right up to the TDM. He has recently added a TDM disarm relay... and I've got an email out to him asking him why also pointing him to this thread. If the disarm relay is what I need then my problems are solved. If not I'm still looking for somebody familar with the TDM circuit and whats expected on each pin of the TDM during arm and unarmed conditions.
Thanks Again :cheers:


[Modified by billreid1@home.com, 9:13 PM 10/9/2001]

 

Im not sure how the 85 works...if it has a switchs around the keyhole, they tend to go bad.

My 86 door switches on both sides went bad...GM upgraded the alarm switch on the keyholes inside the doors with a better switch.
The metal contacts they used corrode over time...my alarm quit working and I replaced the door lock switches and they fixed the problem.I was able to diagnose the problem easily...I began to have to turn the keyhole 2 times or more before it worked.
Thats when I knew the door switches were bad.

I may have vats but had the same symptoms as you said...no matter which way I turned the door key,the alarm either stayed off or on.
Had to play with the switch on and off until it worked.(Key in the door back and forth several times)

Also Depending on if i used the power door locks to activate it or not.
If its the module and ya fix it ,let us know the results...always curious what those fixes are.

Also,If the 85 has these alarm switches on the door locks inside the door, check them...youll be able to see if they rusted internally or not.





[Modified by Bill's86Coupe, 12:59 AM 10/10/2001]

 

Thanks for all the responses... keep them coming. For now I'm going to pull the door panels and check the key lock arm/disarm switches. I tried the driver door with a key and nothing happened... the security light just keeps blinking. Normally I only use my my keyless entry system to lock/unlock. I suppose I actually need to turn a key in the lock to arm and disarm the TDM? Also, Brian responded back and stated I need an additonal relay to disarm the TDM because the keyless entry uses the door locks and not the switches at the door keyholes... once I get it working properly.
Thanks Again

 

ah yes, i forgot about the switches on the key holes. id be willing to bet that one or both of yours is bad. wait a minute, i dont think the passenger door has one. ive locked my keys in my car and had to pick the lock a couple of times, and if you use the drivers door, the horn will go apepoopie. if you use the passenger door, it willnot make a sound. i dont think there is anything in the passenger door for the TDM, atleast on my car anyways.


[Modified by 88L98, 12:21 PM 10/10/2001]