I posted about this before but didnt really get any solution. Here's my situation: Got an Audiovox alarm/remote start and got it installed. Fine unit except that the reception of the transmitter deteriorates when the fan of the climate control is turned on. The higher the fan speed, the less the reception. Basically, at a fan speed of 1, I can open my car after around 5 presses of the unlock button on the transmitter. On a fan speed of 4, I might have to press it 100 times and it is still not guaranteed to receive the signal. I've tried it with the transmitter held right against the antenna and got the same results.

Neither audiovox or the online store that sold me the system will let me return it. The audiovox techs tell me that the heater motor is producing interference and that there's nothing I can do about it.

This is such a PITA and I cant just forget about it, so is there anything I can do about it? I was thinking of wrapping the heater motor in some sort of metal that would prevent the interfering radio waves from spreading. Is anything like that possible? Any other possible solutions? thanks in advance

 

anybody...?

 

Why don't you try mounting the alarm brain farther away from the heater motor??? That's what I would do.

Tony

 

I never thought of that, I thought it all had to do with the antenna. But I'll try, thanks.

Anyone know exactly where the motor is or have any other suggestions?

 

I haven't the slightest clue as to how your alarm remote actually reaches the brain. It might have a small antenna wire that comes out of it. Is the brain mounted under the dash? You might just try re-routing this wire in different locations to see if the problem goes away. If that doesn't work, and assuming it's under the dash, try switching from the passenger to the driver's side or vice versa. Don't permanently wire everything until you can determine if this is the actual problem. Read your owner's/installation manual. Where did you get it installed? Have them look at it.

Tony

 

Also check to see if both are grounded in the same spot or if either ground wire is loose or corroded. The fan speed is not high enough to interfere with RF. At least I don't think so. The fan speed is likely between 30 and 3000 RPM's, RF is about 27 Mhz and up.

 

I know the alarm is grounded to the chassis at a spot under the fuse box on the drivers side. I dont know where the fan is grounded though. and i dont think its the fan speed thats causing interference, i think its coming from the motor which could be spinning faster or sending out signals some other way. I guess I'll try to switch around the antenna and brain positions for now, see how that works

 

So is the problem that you remote start the car in the morning, and the heater fan kicks in to bring it up to temperature, and when you go out to the car to try and unlock it, it won't?

I agree with jmax...there's no way the fan motor is causing interference. I would be astonished if its spinning faster than your typical 1,750 rpm AC motor. If there is a relationship between fan speed and the reception, maybe the installers screwed up. I wonder if they tapped the power wire for the fan to serve the receiver, and that's somehow messing it up.

You could probably test this theory...anyone know of something that would create a similar magnetic field as a motor coil? If you find something that does, you could turn the fan off and that particular thing on, and see if you have the same problem.

 

Try regrounding the fan. It's amazing how simple little things can introduce noise into an otherwise quiet system when the current that they draw increases dramatically. The ground under the fuse box is a sign that they tapped into the fuse box for the power wire for the alarm. Amongst other things it would be real easy to disable the alarm if it plugs right into the fuse box. Other than that all the noisey OEM electrical components in the car use the fuse box. Horn, lights, ECU, PCM, wipers, brakes, heat, A/C, etc.

 

I'll definitely give it a try, but how do I reground the fan?

Also, if it were the motor causing the interference, wouldn't the signal still get through if i brought the remote right up to the antenna and tried to unlock the car? Because I've tried that and it doesn't help at all. The response is the same regardless of distance from the antenna or car.

 

I'm not going to pretend to know anything about antenna's, antennae, whatever they are. Regrounding the fan should be easy. Find the fan, follow the wires, one will go to ground. Just unbolt it, clean the connector and the ground point and resecure. But if the wires are corroded it could take some work and some new wire or possibly a new fan. I doubt that will be necessary but if it is check the local junk yards.

Your ground for the alarm is also a consideration. The ground path may be shared by many other items in the car, including the fan. I think this is referred to as induced noise. But try running a new power wire for the alarm to the battery so that you don't go through the factory fuse box. You will need a 5 or 10 amp fuse and and fuseholder and some 8-12 gauge wire for this.

Before you do any of this other stuff try just holding the alarm brain and moving it around to see if a different location works better. If you find that relocating the brain solves the problem, you are done.