Hey guys,

I've recently encountered my parking and tail lights not turning on. So first i checked all the fuses and all looks good. My headlights, brake lights and signal lights all work fine. Then i noticed my parking lights do turn on when I arm/disarm and remote engine start with my alarm fob. But other than using the alarm, i can't get the tail/parking lights to turn on.

Has anyone experienced something like this? Any suggestions on where I can look and trouble shoot?



Thank you.

 

RX7Link,

I have not experienced this problem.

Is this an aftermarket alarm? You may want to disconnect it and verify the results. If the lights come back on when the aftermarket alarm is disconnected then you could troubleshoot that alarm system. It would also be a good idea to verify your car's built-in anti-theft system. It is embedded in the Body CPU, aka CPU #2. The checks for it are located in the BEM (Body Electrical Troubleshooting Manual).

Let us know what you find!

 

Hi Gen2n3,

Thanks for the reply. I have an old viper alarm that's been on the car since 2004 - ish. This light issue just happened recently, that's why i was partially suspecting the alarm. If I disconnect the alarm, would it reset anything on it? I'll pull the CPU#2 and take a look and update.

Cheers
- Link

 

Link,

I am not sure what would reset if you disconnect the Viper alarm. What do you have programmed on it? I have not used aftermarket alarms in 25+yrs. I would venture to say that if you disconnect it, there would still be some retention in its non-volatile memory. What would happen when your car battery dies? If you unplug the alarm from the power source it should think the battery died. Again, I am no expert in Viper alarms. Do you still have the documentation for that specific alarm model?

It may sound easy to remove CPU#2 and inspect it first but, inspect the aftermarket unit instead because it is a piece of electronic gear that piggy-backs into the OEM system. Not to mention, an aftermarket alarm does not normally account for any other factory anti-theft system. Something else you may consider: some aftermarket alarm systems require a tap into the exterior light system wires. For example, I found a wire splice (a poor one at that) on my Vert's front turn signal. That splice was a tap to an aftermarket alarm that was once installed on the car.

Could you have a splice point (from the Viper alarm) in your external lighting that is shorted to the chassis?

 

Yeah, I would highly suspect the aftermarket alarm or something with the wiring to it. The alarm typically taps into the running lights to flash them when you arm and disarm the system.

May also want to get the shop manual out and trace that circuit, start seeing where the 12v stops in the circuit. Could be the splice for the alarm into that wire finally worked loose or broke and broke the circuit.

Dale

 

Thank you for the replies. Unplugging the alarm unit = disconnecting the battery makes a lot of sense. I've done that to many times to re-learn my PFC idle and never had an issue.

My suspicion is the aftermarket alarm system as well, since this occurred out of nowhere w/out any new installs or tampering. Could be 15+ year old electronics wearing out. I will do an in-depth look at both the viper unit and CPU#2 this weekend and report back.

Thanks again.

 

Looking into this exact issue myself it seems. Was curious if you made any progress on diagnosing the issue?

 

Check your TNS relay