2002 Toyota Tacoma low beams quit working, door locks won't work, no radio, no cruise control what could be the problem? Have checked the fuses and there doesn't appear to be a problem with them. Someone said the ECM could that be it?

  • ECM is unlikely, BCM maybe. Check engine light on?
    – Ben
    Commented Jul 6, 2016 at 12:54
  • 1
    Very unlikely that it's the ECM - that only controls engine issues and (on some vehicles) security. Check for good earths - especially with so many unrelated electrical issues, that's where I'd be looking first.
    – PeteCon
    Commented Jul 6, 2016 at 14:48
  • Time for a schematic and a test light. It is likely one common wire that has caused issues. Start with once circuit and trace it out. Find out where you are getting voltage and where you aren't.
    – rpmerf
    Commented Jul 6, 2016 at 20:12
  • No check engine light
    – Des
    Commented Jul 10, 2016 at 21:54

1 Answer 1


After looking at a ground distribution diagram the cruise, head lights and power door locks share some things in common. Given that some things I assume work and others that obviously don't, it would be isolated to a single branch of the circuit. Unfortunately these splices are located in the dash and the dash may need to be removed or pulled back to gain access.

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ID, IG is the ground to chassis you'd want to look at. And J/B 3 would be the next place to look.

An easy place to check the cruise control system would be at the cruise control computer in the right kick panel. Look for ground on pin 16 (white/black). If you don't have ground on pin 16 gain access to J/B 3 and do a continuity test.

I suspect something in J/B 3 has gone bad or the ground on IG has come loose.

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