Viper 550esp, sometimes works?

Check to make sure you're not accidentley putting it into valet mode vith the remote. In valet mode, it will still lock and unlock and remote start, but the alarm will not arm. The red LED will be steady on(not blinking) if it is in valet mode. Check that next time it happens.

CutDog504 wrote: Check to make sure you're not accidentley putting it into valet mode vith the remote. In valet mode, it will still lock and unlock and remote start, but the alarm will not arm. The red LED will be steady on(not blinking) if it is in valet mode. Check that next time it happens.

Okay.. I tried to check to see if its in valet mode.. but my sirens dont work. Any ideas?

Okay... its not in valet mode. Any ideas?

I believe on that unit, if you pre AUX and then quickly press Arm or Disarm, the unit will arm or disarm silently. That's a feature from Viper. Do you think you might be hitting the AUX button by mistake before locking? Two questions: 1. When the problem happens----when the car locks without making any sound----is the red LED flashing or solid? 2. If the light IS flashing after you've tried to arm it, wait a few seconds, and then verify whether or not the siren works, simply by opening the door with the key.

Chris Luongo wrote: I believe on that unit, if you pre AUX and then quickly press Arm or Disarm, the unit will arm or disarm silently. That's a feature from Viper. Do you think you might be hitting the AUX button by mistake before locking? Two questions: 1. When the problem happens----when the car locks without making any sound----is the red LED flashing or solid? 2. If the light IS flashing after you've tried to arm it, wait a few seconds, and then verify whether or not the siren works, simply by opening the door with the key.

Hey Chris, thats what I thought at first too, but Im not hitting the aux.   To answer your questions.

1. When this happens. The LED is flashing.   2. And sometime when the alarm is triggered, only the lights flash and the siren doesnt sound.

Do you think its a problem with a short in the siren somewhere?

Thanks for the help!

Yes, that does sound like a problem with the siren. Not necessarily a short, but some kind of problem. The Viper siren is shipped with a long pair of wires---red and black---it is intended that these two wires be run through the firewall and inside the car. Then, the installer would (inside the car) ground the black wire, and connect the red wire to the brown wire coming from the alarm brain. BUT, some installers cut the black ground wire short, and ground the siren under the hood instead. It saves time, but the underhood ground can be more likely to corrode or have the screw come loose. Anyway, now that you have an idea how it works, time to check stuff out. --Find out how the siren was grounded, and inspect that. --If you can get behind the dash, inspect the connection of the red siren wire, to the alarm's brown siren output wire. --Look at how/where the siren wire runs through the firewall, and see if it is getting chafed. --Look at the siren itself? It is intact and mounted properly? Or have the screws come loose and it's flying around hanging from its wires? You can get sirens pretty cheap on eBay, and almost any brand would work. (Are you near Boston?). If you're handy with tools, it might be easier to just replace and rewire the whole thing.