WHY DO SIGNAL LIGHTS BOTH FLASH WITHOUT 4WAYS ON

  • Tiny
  • ultimate_taxi
  • 1988 Chevrolet Truck
  • 160,000 miles

Why do signal lights both flash without 4ways on

Monday, October 22nd, 2012 AT 11:17 PM

13 Answers

  • Tiny
  • caradiodoc
  • Expert
  • 24,980 posts

I assume you mean they flash in all four corners when you turn on the turn signal. If that is right, check the trailer wiring harness to see if the wires are chewed up and touching.

Was this
answer
helpful?
Yes
No
Monday, October 22nd, 2012 AT 11:32 PM
  • Tiny
  • caradiodoc
  • Expert
  • 24,980 posts

Also check if the 4-way flashers are non-functional but the switch is turned on. That will connect the two sides together electrically.

Was this
answer
helpful?
Yes
No
Monday, October 22nd, 2012 AT 11:34 PM
  • Tiny
  • ultimate_taxi
  • Member

Checked trailer connect still does when unpluged would 4way switch cause headlight connection to flash as well

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 12:15 AM
  • Tiny
  • caradiodoc
  • Expert
  • 24,980 posts

You didn't mention anything about the head lights. If you have multiple lighting circuits involved in this problem, check if they're all dimmer than normal. A bad ground will cause the current through one bulb to seek an alternate path to ground, and that is through another bulb(s), but since the voltage splits among them, none will be full brightness.

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 1:36 AM
  • Tiny
  • ultimate_taxi
  • Member

Any suggestions on where to start looking

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 2:25 AM
  • Tiny
  • caradiodoc
  • Expert
  • 24,980 posts

You didn't say if the lights are dim or full brightness. If a ground wire is the problem, you can prove that by removing one bulb. If that causes any other bulb to go off, it's a ground problem. You can also remove all the affected bulbs but one, then check if that one works right. If it turns on with the wrong switches, there is a different wiring problem. Most commonly two wires are touching such as the trailer wires I mentioned. An aftermarket radio that is wired wrong can do that too. There's a wire to it for the tail lights and one from the dash lights.

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 2:40 AM
  • Tiny
  • ultimate_taxi
  • Member

Funny you mention radio because there is and someone just cut wires off at plugs

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 2:46 AM
  • Tiny
  • ultimate_taxi
  • Member

Thanks for help got it fixed

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 10:26 PM
  • Tiny
  • caradiodoc
  • Expert
  • 24,980 posts

What gremlin did you find?

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 11:08 PM
  • Tiny
  • ultimate_taxi
  • Member

Radio wired wrong found two broken grounds in front end one wire for radio kept blowing tail light fuse

Was this
answer
helpful?
Yes
No
Tuesday, October 23rd, 2012 AT 11:25 PM

Please login or register to post a reply.

Similar Questions