Engine/Transmission (1998.5 - 2002) Flashing lights

[MEames]

Several days ago I started my 99 Truck and the lights started flashing. I get three sets of thirty flashes so am guessing that it is a code. I hooked up a cheep code reader but it says their are no engine or transmissions codes stored. I told it to erase codes but it said there were none to erase. I disconnected the batteries for about 30 min and hooked them back up. I still get the 3 sets of 30 flashes. The truck is running good. I need some insight into this.

 

[Missouri Mule]

Which lights are actually flashing? Check engine light should come on if you have codes stored.

 

[MEames]

Thanks for the response. My check engine light does not come on but the 4 way flashers do, my radio display, and I think my dash lights.

 

[Joe Mc]

What lights are actually flashing, headlights, dash lights? ? ? Does the flashing start immediately upon start up, or if you turn the key to the on (wait to start) mode? Need some more details in order to try to help. My 99 never flashed any of the lights so I'd like to try to help you, but . . .

 

[MEames]

The 4 way flashers, odometer, & stereo lights start flashing as soon as I turn the key on. it gives me 30 flashes then a pass and thirty more with another pause then a final set of thirty. The truck runs fine other than that. I have put about 1 ,000 miles on it since it sarted doing this 3 weeks ago.

 

[Joe Mc]

May sound odd (but not as odd as what's happening to your truck) have you checked/cleaned all battery posts and cable lugs, checked all grounds, eng to body, body to frame, even grounds under the dash, ECM/PCM to body. Sounds like there's more of an electrical oddity going on than anything else. At least the truck is running good. Please let us know what you find so we can ponder what the next step could be.

I wonder if your Hazard Flasher (actual device that signals flashes) could be bad/shorted internally?? See if there's another member close to you that's willing to swap some things for test purposes so you're not throwing parts at it without knowing for sure first.

Oh, "every time" you shut down and go to start back up, wether it's an hour or a minute, the lights flash as stated?

Can't wait to see what this one ends up being. Good luck Bro.

 

[MEames]

I have cleaned the battery terminals but not checked for any bad grounds. The other interesting thing is that the flashing starts as soon as I turn on the key and even If I turn it right back off it will still go throught the first sries of 30 flashes.

 

[Road Dog]

The 4 way flashers, odometer, & stereo lights start flashing as soon as I turn the key on. it gives me 30 flashes then a pass and thirty more with another pause then a final set of thirty. The truck runs fine other than that. I have put about 1 ,000 miles on it since it sarted doing this 3 weeks ago.

That sounds just like the aftermarket alarm system on my truck. It's connected to the parking light system (which includes the dash and radio). A lot of city/county noise bylaws state that a car alarm can go off three times and then must reset.



If you unlock using the remote then it should (might) turn off the alarm. It might auto-arm after the vehicle is shut down.

 

[BEnglish]

If I remember reading my FSM correctly, the OEM alarm uses the CTM, and if you have an aftermarket alarm, the installer may have connected to it or its wires in some way.

 

[MEames]

Problem disapeared yeserday. I started the truck up to go home after work and no flashing. We finally got some dry weather after 2. 5 weeks of rain. May have been a bad connection but no way ot knowing unless, it acts up again when we get more wet weather.