Honda Civic - Ignition Kill and Lo-Jack

Hi,

I have some experience tuning cars, and may be able to point you in the right direction. First, if the system works when the weather is warm and dry, then your problem is likely a loss of good ground or moisture infiltration into the lojack system. What you should start with before switching ignition parts, is to follow and identify all components of the lojack system. All terminals will need tightening, plus a treatment to drive out moisture, followed by a thorough coating of brush on rubber, or heat shrink tubing. The connector clips and wires on add-on units are almost always the cheapest possible, and it sounds like they are allowing infiltration under moist conditions.

Second, you should construct or purchase a housing box for the lojack control unit. It will need to be totally isolated from the environment, meaning it must keep out moisture, dirt, oil, etc., and also hopefully minimize vibrations as well. If you purchase a plastic box, add cutouts for wiring, and line it with foam padding plus proper gaskets, the environmental issues should be minimized, and hopefully you will not have any problems in wet weather.

Mike Lynch

I have a similar problem with the alarm system installed in my Toyota. I've had several episodes where when the weather here in Houston gets near 100° F the keyless remote will unlock the car but will not disable the alarm causing the alarm to sound when the door is opened. I've taken it back to the dealer to have it fixed three times. Now that it is out of warranty, it has started doing it when it is at or near freezing. I suspect that there is some kind of plastic connector (like a screw down terminal block) that is expanding and contracting with temperature and causing the poor connection to occur.

Another possibility is tin whiskers. Ever since the EU has mandated ROHoS compliant electronic equipment, most manufacturers have gone to a pure tin solder (vs the really expensive gold/indium/tin alloys). The problem with Tin is that over time it will grow almost microscopic whiskers that are conductive. Adding lead to the solder prevents whisker formation but when you take the lead out you have a problem. Whisker growth is especially bad at elevated temperatures (like under a car hood.). This has been a known phenomena since the 50's. (several of the earliest satellites used pure tin solder due to it's high melting point. Many of them failed prematurely due to this.) Why the EU got the bright idea to take lead out of solder is beyond me. But then again, there isn't much that the EU does that makes much sense.