troubleshoot, sunfire, scytek visionguard 8000-m

So I have a ScyTek Visionguard 8000-M. I previously installed it myself in my 1997 Sunfire, and then transferred it to another sunfire 2 years after. Everything was working great until recently. 1) My 2 way remote can't communicate with the alarm 2) The valet switch seems to have no effect 3) The alarm is always armed - and I cant disarm it. So every time I open the car door it sets off. I had to disconnect the door trigger wires to the alarm 4) I have a starter-defeat antigrind installed (as described on page 25 of the user manual - see above link) - so theoretically the car shouldn't even start while its armed, but after disconnecting the door triggers I can enter, start and drive the car no problem) What on earth could be happening? I tried disconnecting my battery for 10 minutes to reset it, I check the ground wire to make sure it was secured and I'm seriously at a loss. I can't even enter programming. Any help would be greatly appreciated.

DMM to your ground and your power inputs, sounds like you have either a bad ground or no power.

I used my multimeter on the ground to check for continuity - it checked out. Then I checked for voltage across the power and it was +11.4V - I checked every bloody fuse in the car and they check out also. It's frikin weird!

Frankly unless your DMM needs calibrating, a fully charged battery should read 12.6VDC off load, make sure your DMM is close to that reading. If so that voltage is borderline, test continuity from your grounding point to the battery NEG. It should be under 2 ohms.

y2j514 wrote: I used my multimeter on the ground to check for continuity - it checked out.

Continuity.... how? Resistance, or the continuity checker? The latter usually isn't suitable (its continuity can be several tens of Ohms). (Power) Grounds should be milli-Ohms or less, and that's pretty difficult to measure. (Yes, I know a sticky hereon says "less than 1/2 a Ohm" - and that's fine if you really want to place a headlight bulb in your ground path. But I suggest 1/2 a MILLI-Ohm is more like it - noting that I am talking about high-power grounds, not grounds of up to a few Amps... (at 0.5 Ohm, ever Amp adds a 0.5V drop).)

I got my figures wrong and Oldspark is quite correct, grounding is absolutely critical.

I used the continuity checker originally, but then checked using resistance. It was super low resistance, but I forget the value. It's raining/snowing outside today and I have class all day so hopefully I'll be able to tackle it some more tomorrow. I'll check the ground wire resistance right to the negative battery terminal - and I'll also take a look at the power supply lines too.

Look again at my first post. Which is why I questioned the 11.4V reading.

So I finally had some time to do some more investigating. I'm busy with final exams and the what not. So as I mentioned I checked all the voltages and everything was good. I checked the resistance and the 2 main power wires had a resistance equal to infinity (on my meter it read (1   ). I took a closer look and saw that the fuses for each wire were fried. They were not blown though, but severely melted. I attempted to replace the fuses with small 5 amp fuses to see if anything would happen - nothing. But the fuse holder itself is melted and mangled. I'm going to try replacing those in the near future. Hope that I found the problem. As to WHY they fried? I am still looking into it.

Poor quality fuseholders? I've had a similar problem with a Viper unit here, one of them blown. I simply changed the fuseholder, the problem went away.