problem with 2004 f 350 and avital 4300

Here is the whole scenario.
4 years ago I had a shop install an alarm/ remote start. I have been out of the business for awhile and frankly became a bit lazy and since I could afford someone else to do it that is what I did. It was an Ungo but dont remember which one. Anyway it worked fine for about a year but then started false alarming and keeping the brake lights on. This went on for a few months when I finally had enough. The actual installer who did it had since then opened his own shop so I went there the second time. Told him the problem and that I wanted a different one installed and this time had an Avital 4300 installed. Again this worked for about a year with no problems and then this second one started doing the same thing. It was false alarming (though not as much as the Ungo) but it was keeping the brake lights on alot. So much that it started to drain the truck batteries (there are 2), so I disconnected the unit. Since disconnected for 4-5 months now the truck has been fine. I mention that to eliminate the possibility of the truck having a problem. Anyway, it is starting to get cold again and I really need the remote start.
My questions are: does anyone have a solution to this? Maybe there should be a diode somewhere that wasn't put in? Should I gat a third different unit and see what happens?
Any help would be great, thanks.

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no one has an idea?

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Hmm.

I understand your opinion that if two different units did the same thing, and that disconnecting the system made the problem go away, and so it would seem like the truck doesn't have a problem.

On the other hand, I've never heard of a remote starter's brake input suddenly turning into an output. And it seems like a big coincidence that two units, from two different brands, would do the same thing in one car.

And yes, like you were thinking......even though we installers never generally do this, putting a diode between the truck's brake wire, and the remote starter's brake input, would certainly keep the remote starter from being able to send power to the truck's brake circuit.

I don't know if you've ever looked at a brake pedal switch on a Ford, but they're mounted to the pedal linkage in a kind of "floppy" way, for lack of a better word. Even handling the switch while connecting the brake wire, the car's brake lights go on and off.

Is it possible the installer's brake wire was a little too short, and was pulling on the brake switch? Or maybe the brain was mounted too closely, leaning on the switch sometimes?

When the Ungo was removed and the Avital installed, were all the wiring and plugs changed, or were some of them reused? If the Ungo unit was newer, it should be a DEI product just like the Avital, and therefore the installer might have been tempted to just reuse the existing wiring.

If this were my truck, I would do the following:

1. Disconnect and remove the ENTIRE installation from the truck, every wire.

2. Carefully inspect the brake switch. It might even have some sort of adjustment. If there's any doubt, maybe even replace it, as they're not very expensive. (Less expensive than a pair of batteries, anyway.)

3. With all fresh, new wiring (and even swap out the Avital brain for a new one if possible), carefully and neatly reinstall the unit.

4. Get the brake connection at somewhere other than the brake switch. I think there should be a trailer connector under the dash somewhere that will have the brake wire in it. Also put a diode inline to take away any more possible doubt.

Awesome info, that is what i needed, thanks......the ungo was a dei unit, when i had the avital put in i told them i wanted it all new (not using the old wiring connections)....but i dont know if that was done, i just figured since it worked with no problems for awhile they did the right thing....anyway, i did check the brake pedal switch and it was fine, but what you say makes sense about the wire pulling it at that location if it was indeed connected there, i wll check that out..hopefully i will that was it and correct the problem..if not i will get into it more......
Thanks again for taking the time to post, much appreciated

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One more question.....
the vehicle is a diesel....if i have to replace unit which should i consider that has the wait to start built in without using any extra relays or anything else....i also want it to work long range....while the avital is pretty good it doesnt even compare to the ungo which i could start from a ridiculous distance, even inside a building or restuarant

Hey, no problem.

I install Audiovox so obviously I'm a little biased, but their units do have a programmable diesel delay. You can select 10, 15, or 20 seconds. I would wait until a really cold morning, and measure how long your wait-to-start light stays on.

I've never measured the range of the Audiovox units but noone complains. Their basic units claim 1000 feet, and they have so-called "one-mile" units too.

Basic RS/keyless: Prestige APS-687 or APS-57. Long-range RS/keyless: XR6900 Long-range RS/keyless/alarm: XR9000.

DEI units seem to have a LOT of different antennas with different ranges: XHF, HF+, and so forth, marked on the antenna.

If you go with DEI again, maybe someone on here who knows their product will be able to point you in the right direction.

P.S. The Avital that's in there, other than your range complaint, is probably fine, isn't it?

Maybe you could get the guy who installed it to open up a unit that's already defective but has good wires.....swap all your used wires out with new ones.

Then you could do a fresh install, and maybe at the same time look for one of those extended range DEI antennas to correct that issue. Then you wouldn't have to buy a whole new system.

i used to install audiovox/prestige back in the day....i do like their product.....

Anyway, dude you are the freakin man!
It was the wire that was tight and moving the brake switch......I redid it and everything is great.....it's been 15 years since i installed regularly so my mind isn't geared to troubleshooting anymore .....thats why i posted and you hit the nail on the head.......
Again, thanks a million