1987 Chevy Astro Turn Signal problems

Tiny
BOBALUBOB
  • MEMBER
  • 1987 CHEVROLET ASTRO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 20,000 MILES
My 1986 Astro van has over 200,000 miles on it. Recently the turn signals stopped working. One strange thing at this time was if I stepped on the brakes the parking lights and brake lights would come on without having any lights switches turned on.

I replaced the turn signal swith this weekend. After replacing the switch the right turn signal had a light, rapid flashing and the lights were barely visible on that side from outside the vehicle. Left side worked fine. They worked a couple of times and then just stopped cold on the way to the parts store.

I bought a new flasher just to see if that would help. It didn't seem to make any difference in the parts store parking lot so I bought a couple of bulbs. On the drive home (no new bulbs installed) it worked fine with both directions bright and distinct. My wife drove it this morning and it worked for one turn and then quit. Any suggestions on how to trace this down greatly appreciated. I am a true electrical novice when it comes to anything beyond changing parts.
Monday, November 3rd, 2008 AT 4:31 PM

13 Replies

Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
Check the grounds to your beake lights and front turn signals. The easiest way is to remove the bulb and run a test light from battery "positive" to the ground terminal in the socket. Your test light should light if ground is good. If not, check the system ground(s).
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Monday, November 3rd, 2008 AT 11:03 PM
Tiny
BOBALUBOB
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James,

Thanks for the tip. I will check out the grounds as soon as I can. It is more difficult with the time change.

Would a bad ground cause the parking lights and tail lights, and the tone for the key, to come on when I step on the brake pedal with the car not running, no key in the ignition, door open? I am guessing that this part of the problem suggests a short somewhere. If so can you suggest where I would begin looking for that?

Thanks.

Bob
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Tuesday, November 4th, 2008 AT 2:41 PM
Tiny
JAMES W.
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Bob, Open grounds in a car do weird things. If a light in a vehicle loses ground, it will take anything close to it and try to use it as a ground. Lets try something. Turn the key to "on", turn your left turn signal on, then step on and hold the brake. Does the left brake light blink? And, does anything strange happen to your signals? If I'm right, in a sense it is a short, but it's backwards. Let me know what you find, Jim.
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Tuesday, November 4th, 2008 AT 3:52 PM
Tiny
BOBALUBOB
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Jim,

First I checked the fuses when I got home. I have been checking the turn signal fuse but this time checked the brake light fuse too and it was fried.

With the key turned on, left turn signal on, the left rear and front turn signal lights flash. When I applied the brake the left lights kept flashing normally.

When I switched to the right turn signal both rear signals, the dash light and the license plate lights all flashed. When I then applied the brakes the left rear signal stopped flashing and brightened like a brake light should. The dash light and front turn signal keep flashing.

When I pulled the left rear flasher bulb and turned the left turn signal on I got a normal response with my test light. [I can't find my multimeter, of course] Now, when I turned on the right turn signal and tested the left socket with my light, the hot terminal did nothing, but the ground terminal gave me a flashing light. The license plate light was flashing as well.

This is as far as I have gotten. Does this provide enough information to help narrow it down? I am open to trying any suggestions you have.

Thanks,

Bob
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Tuesday, November 4th, 2008 AT 9:06 PM
Tiny
JAMES W.
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Bob, your hot on the trail. You definately have a ground problem somewhere in the rear. My locator system is down (I'm working on it now) or I would send you a diagram of all the ground locations. As soon as I get back on line I'll send you a copy. Do you have, or have access to, a fax? Jim.
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Wednesday, November 5th, 2008 AT 1:59 PM
Tiny
BOBALUBOB
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Jim, Yes I have access to a fax at work. Just make it attention Bob Brown.

405-466-3459

Thanks,

Bob
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Wednesday, November 5th, 2008 AT 2:26 PM
Tiny
JAMES W.
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Bob, just to let you know I haven't forgotten you. I'm still trying to find a diagram for wiring and ground locations, Jim
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Thursday, November 13th, 2008 AT 1:42 PM
Tiny
BOBALUBOB
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Jim,

Thanks for the update. I was a little concerned. My wife will be relieved if you can help me track this down. She is the one that has to drive this old beast.

Thanks,

Bob
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Thursday, November 13th, 2008 AT 1:46 PM
Tiny
JAMES W.
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Fax is on it's way. It's not very clear. Hope this helps, Jim.
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Thursday, November 13th, 2008 AT 3:20 PM
Tiny
BOBALUBOB
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Thanks Jim,

I got the fax. Any suggestions on what I should do or where I should start to try to narrow this down?

Thanks,
Bob
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Thursday, November 13th, 2008 AT 3:35 PM
Tiny
JAMES W.
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I tried to find a "ground" location diagram, but apparently there isn't one available for Astro. The only thing I can suggest is to start at the back end and test your ground connections from the light sockets forward until you find a bad one.
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Thursday, November 13th, 2008 AT 3:49 PM
Tiny
BOBALUBOB
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Jim,

I will give it a shot. I'll let you know what I find.

Thanks again,

Bob
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Thursday, November 13th, 2008 AT 3:52 PM
Tiny
JAMES W.
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Bob, let me know what you find out when you get a chance, Jim.
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Friday, November 14th, 2008 AT 7:26 PM

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