jfadams

The security system (aka alarm system) on my 1999 4Runner SR5 4WD recently failed. The SR5 came with the security system, which might have been installed at the port by Gulf South distributor. I have replaced the battery in the fob several times in years past. This time the red light on the lower dash to the left of the is no longer lit. Asked the dealer to check the security system while the SR5 was in for other repairs beyond my skills. Dealer could not quickly find the source of the problem, and suggested it would be cheaper to have an alarm shop install a new security system.

When I got the SR5 back I noticed that the fog lights no longer worked. The SR5 was pre-wired for the fog lights and were dealer installed in ~ 2000. Perhaps coincidentally the fog light switch is next to the security system light on the lower left dash.

Already check the fuses for the fog lights and security system which look fine, but replaced them just in case.

Removed the fog light relay and there is 12 volts of power to the front right socket in the fuse/relay box area for the fog light relay. With the relay out, I also tried jumping the front right relay socket to the front left socket, and then starting the engine and turning on the low beam lights (as someone suggested in another post), and the fog lights did not come on. The other post opined that such condition indicated a problem in the fog light wiring or burned out fog light bulbs. I tested the bulbs and connectors; both were fine. Traced the wiring from the fuse/relay box to the low beams and fog lights; found nothing unusual.

The timing of the failures and the proximity have me baffled.

No prior problems with either system.

Any suggestions? Thanks in advance.

jfadams

BTW: After studying the 2002 fog light wiring diagram, I just realized that I could have ruled out a burned out bulb or a fault between the relay and the fog lights by simply jump testing sockets 3 and 5 (not 1 and 2 mentioned in an another post), assuming that diagram also applies to a 1999 4Runner. Will try that test as soon as possible.

Also noticed that the "Daytime Running Light Relay (Main)" is a common point in both the fog light circuit and the "theft deterrent" circuit. Hmm ...

wyoming9

iTrader: (1)

You say Failed In just what way?/

That might help to isolate the issue

jfadams

old87yota

Is this the type of security system that prevents the vehicle from starting or one that just sounds an alarm when someone tries to break in?

If you are pretty sure the two issues are related, try to diagnose the fog light problem on its own, without trying to fix the security system. The fog lights should be easiest to diagnose. Once you find the problem for the fog lights, you may find the common failure point, or find out there are multiple problems.

jfadams

Following the advice given by old87yota I addressed the fog light issue first.

After testing the fog light fuse, relay, switch, main relay box in the engine compartment, wiring under the dash, and wiring in the engine compartment, I finally found the culprit was corrosion inside the fog lights (Hella Micro DE). Both fog light were so covered with a white chalk-like deposit (aluminum oxide?) inside the housing that I could not get a good continuity test across the aluminum grounding plate with an ohm meter! The base of the H3 bulbs relies on 3 tiny points on the grounding plate to serve as the ground contact for the bulbs. Bad design in my opinion. I carefully ground the corrosion off with a Dremmel and re-installed the fog lights: Success!!!

Plan to tackle the alarm system next. Found the "Toyota V.I.P. Security System Electronic Control Unit" (Model RS2000) and "Toyota Glass Breakage Sensor Electronic Control Unit" while searching under the lower dash. The unit does not seem to receive any signal from the key fob (even after replacing the fob battery) and the red dash light to the exterior of the steering wheel by the glass breakage detector does not light even when the door is locked with the key. Does anyone have any experience with this alarm system?

Thanks.