Door lock question

[SonnysSweetTea]

So on my 98 ecsb k1500. 4 years ago I bypassed the factory keyless and installed a viper alarm myself. For 3 years it's been perfect. About a year ago the key fobs will only unlock the doors and disarm. But when you arm it, it doesn't lock the doors. You can hit the lock switch on either door manually and they work normal. I've looked for relays or fuses but haven't seen any. I've been told it could be the actuator, but wouldn't it keep even the manual switch from working too? I'm confused at what I should do to fix this. I'm tired of manually hitting the lock switch every time I get out to lock the doors especially when I forget and have to walk back. Any help would be appreciated.

 

[df2x4]

I'd look for a reset procedure in the manual for your Viper system. I've had aftermarket keyless systems do weird stuff that resetting the brain fixed a few times.

 

[kennythewelder]

I have had a Viper alarm in my truck for years. Mater of fact, Im on my 2ed system because the 1st system failed after about 10 or 12 years. Anyway, I have never had an issue like yours with my systems, but how does the door lock and unlock with the switch on the door. The motors that work the locks do get weak in time. I have had to replace mine once or twice since I bought my 97, used in 2002. The Viper system does not trip the door lock for very long, so if the lock motor is weak, it could cause a slow locking not letting the viper lock the door. One the other hand, if the locks do nothing at all, then the control unit may need to be replaced, as long as the lock is not getting a signal. All of what the system does ( the control unit that is) is all in low voltage, so it all goes to relays before it controls anything. These relays can be placed anywhere in the truck, as can the control unit. Mine is all under the dash, and close to the steering column. IDK where yours is, but I would think its in the same area.

 

[SonnysSweetTea]

I have had a Viper alarm in my truck for years. Mater of fact, Im on my 2ed system because the 1st system failed after about 10 or 12 years. Anyway, I have never had an issue like yours with my systems, but how does the door lock and unlock with the switch on the door. The motors that work the locks do get weak in time. I have had to replace mine once or twice since I bought my 97, used in 2002. The Viper system does not trip the door lock for very long, so if the lock motor is weak, it could cause a slow locking not letting the viper lock the door. One the other hand, if the locks do nothing at all, then the control unit may need to be replaced, as long as the lock is not getting a signal. All of what the system does ( the control unit that is) is all in low voltage, so it all goes to relays before it controls anything. These relays can be placed anywhere in the truck, as can the control unit. Mine is all under the dash, and close to the steering column. IDK where yours is, but I would think its in the same area.

I looked everywhere last night for a relay coming off the alarm module, the only place I didn't check was inside the actual door yet so I'll have to look there tomorrow when I have time to take the panel off. And as for the manual switch on the doors they have full strength unlocking and locking since the day I got the truck, there was one time before I ever had the viper system that the drivers lock felt like it got weak locking the door but it was just getting stuck from the linkage sitting for 5 years before I bought the truck. Grease fixed that issue though.

 

[SonnysSweetTea]

I'd look for a reset procedure in the manual for your Viper system. I've had aftermarket keyless systems do weird stuff that resetting the brain fixed a few times.

That's not a bad idea, my only issue at the moment is I have absolutely no idea which model I have to even find a manual for it lol. I'll have to take a pic of the module and see if I can read a number off of it, unless I can find the book for it somewhere. I'll try that tomorrow also

 

[someotherguy]

You installed it, or you had it installed?

Since it sounds like the factory lock switch locks the doors, my first suspect would be where the alarm taps its "lock" wire into the factory harness.

I wouldn't expect a later model install like yours to have added relays, but instead tap in to the factory harness and utilize the existing relay. However, if an installer added relays, they could easily be the problem as the aftermarket stuff usually doesn't last as long as OEM. I've found them hidden in poor locations like inside the cab sheetmetal behind the kick panel plastic; moisture can get to them and cause corrosion. Found this in a '94 Suburban install where the locks were stuck in "unlock" mode. Unnecessary relay addition example as even the early model 4-doors like the Suburban have a factory relay, whereas an early 2-door truck would not. Your '98 should have a factory relay regardless of model.

Richard

 

[kennythewelder]

Richard could very well be rite. When I had my 1st Viper installed, the Girl did a good job. When it went out, I ordered a new system from amazon. Viper will NOT warranty any system that is not installed by a certified installer, because the system runs on low amps. Any draw on the system that is not low amps, will short out the control unit. So when I got my new system in, I dis the swap myself, but it was a plug and play swap. Like Richard said, check that you have supply wire voltage for the locks going into the module, if so, the check that it has voltage coming out when the locks are activated of course. If you dont have the wiring schematics, I think you can get them from Viper.

 

[kab96shortbed]

I have a 96 Sierra which had a dealer installed Chapman alarm which stopped working recently. I had a stereo shop remove it and attempt to put back to factory config. Everything works as expected except that the truck no longer locks itself when put in gear or unlocks when put in park like it used to. I also tried to jumper terminals 4 and 8 to program some new key fobs and that also didn't work. I am pretty sure there was a connection missed being put back the way it was built when the alarm was removed but am having difficulty locating a wiring diagram for the locks.

 

[someotherguy]

I have a 96 Sierra which had a dealer installed Chapman alarm which stopped working recently. I had a stereo shop remove it and attempt to put back to factory config. Everything works as expected except that the truck no longer locks itself when put in gear or unlocks when put in park like it used to. I also tried to jumper terminals 4 and 8 to program some new key fobs and that also didn't work. I am pretty sure there was a connection missed being put back the way it was built when the alarm was removed but am having difficulty locating a wiring diagram for the locks.

That was a function of your aftermarket alarm; GMT400's do not have that feature originally. It began in GM fullsize trucks with the GMT800 (99-up redesign.)

Richard

 

[kab96shortbed]

That was a function of your aftermarket alarm; GMT400's do not have that feature originally. It began in GM fullsize trucks with the GMT800 (99-up redesign.)

Richard

makes sense, thanks for the info.