Theft light blinking while driving

[Kidd7]

This has been reported by my wife who drives ol Red every day. 2000 Ex v8 Eddie Bower. Intermittently the theft light will blink while driving and the radio resets, loosing it's memory and settings, this is an aftermarket stereo. No drivability issues. There was 1 incident of no start yesterday, but I can not confirm it was PATS related.

This sounds like a power issue to me, maybe even a loose connection. Any input on what wiring would be common to both PATS and the stereo?

 

[J_C]

I would first look at battery terminal corrosion, battery terminal clamp to wire corrosion, and battery cable ground point corrosion. Otherwise there are wiring diagrams linked in my sig below.

Beyond that I would monitor charging system voltage while running and battery health (voltage) when not.

 

[Kidd7]

Batt is 12.7v it drops to ~11.8v when starting, then 14.3v even with lights on. Does not increase with RPMs. That sounds like a good electrical system. The terminals are a little dirty, but no corrosion, none on the mega fuse either. Will monitor.

 

[J_C]

edit: Nevermind, I was going to suggest the ignition switch but then I forgot that the radio loses memory which that shouldn't cause, AFAIK.

Radio memory is preserved with volatile memory that needs power through fuse 29, which is not listed as being used for anything else. However fuse 28 is used by both the GEM and radio, and switched on in ignition start position, so I might look at that and the ignition switch still, but I don't see the direct cause for the radio to lose memory, and I didn't think PATS was in the GEM. You should probably just ignore me.

 

[410Fortune]

The theft light is controlled directly from the pats module in 98-01 explorers there is one wire directly from the module to the instrument cluster

Odd that it will flash while driving

The module is located behind the passenger airbag

Pats and the stereo do not share any wiring connections or fuses

Any chance a wire was pinched or punched when the stereo was installed?

I cannot think of any other way the theft light could be flashing while driving unless you are having power issues at the battery or ignition switch? Or a fuse / relay or power diode

 

[Kidd7]

maybe a pinched wire that became a latent failure, the stereo has been installed for about a year. I'll have to get in there and look for loose / damaged connections.

 

[Turdle]

Could it be the tranciever in dash and radio share ground?

 

[Kidd7]

Thought about that also. I pulled the stereo, inspected wiring, wiggled and jiggled and no resets. So continuing to monitor.

 

[410Fortune]

G100 is a main ground many many things ground here
G100 is 3 pages in the wiring
Book


The theft light in the instrument cluster is activated by one source, one wire. as far as I have ever known? Pretty familiar with the 98-2002 pats system with the module behind the passenger airbag

I would try a google search first reasons why theft light can flash while driving.. strange!

 

[410Fortune]

Connector c212 m and f pictured
You can see circuit 343 dark
Blue with light green pin 6, dead ends?

Likely done in preparation for the next generation of pats (pats e I believe) where the theft light is activated by the pcm and there is no module behind the passenger airbag


C212 is a bulkhead connector from dash to truck buried up inside the dash

 

[Kidd7]

This morning the truck wouldn't start, had driven to the store and wouldn't start after coming out. No lights, no ding, no power locks; it was acting as if the battery was disconnected. I traced it back to a bad ground. I took both battery terminals apart, cleaned and clamped the neg & pos wired back on. reattached everything and she was good to go. The short negative jumper from battery to radiator support had some of the wire strands broken off. My plan is to replace that jumper with a new wire.