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1990 C/K codes?

chowderhead72

By chowderhead72
in Ask A GM Technician

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chowderhead72 Enthusiast

chowderhead72

Posted
Posted

I have a 1990 K2500 8lug w/5.7 with 65,000 miles. Recently my speedometer stopped functioning for a few minutes and when it came back the warning light for the brakesstarted to blink in a pattern: 9 short flashes and 1 long flash. The brakes feel fine but the flashing continues. I have checked the fluid level: centered between full and add. I see no wires disconected an 5,000 miles ago the brakes were still looking great. Any Ideas? Is the flashing light pattern a code or am I just imagining new technology on an old engine?

Please advise

Tom

Wingnut Senior Enthusiast

Wingnut

Posted
Posted

Going from my memory (which is sketchy on a good day) of events more than 10 years ago....I believe that it means you're going to die.

 

 

 

 

 

 

Seriously, I think it's something with the ABS. It has been more than 10 years since I saw that.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted

You add the long flash to the number of short flashes to come up with the code. 10 in this case, which indicates a brake switch/circuit fault. With your comments about the speedo, I would expect to see a code 9, loss of speed signal. Are you sure you counted right? It flashes pretty fast.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
9 short flashes and 1 long flash means its time pour on the gas and light a match.

 

 

 

 

Boy, you're in a frisky mood today. And I'd appreciate it if you don't include a quote of mine, which you have modified so it's not even accurate, in every response you make.

chowderhead72 Enthusiast

chowderhead72

Posted
  • Author
Posted

Thank You GM tech!!!!

 

Now suppose I did miscount and I got a speed error now that the speedo is back to normal how do I get rid of the blinking (Short of pouring gas and lighting....)? My brake lights work fine so I think you are right. If I take no corrective action am I in any danger of brake failure? Do I just need to reset and move on? How?

redvett Senior Enthusiast

redvett

Posted
Posted
Thank You GM tech!!!!

 

Now suppose I did miscount and I got a speed error now that the speedo is back to normal how do I get rid of the blinking (Short of pouring gas and lighting....)?  My brake lights work fine so I think you are right.  If I take no corrective action am I in any danger of brake failure?  Do I just need to reset and move on?  How?

 

 

 

 

To remove the code unhook the harness from the RWAL unit under the M/C with Ign. in off position.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
Now suppose I did miscount and I got a speed error now that the speedo is back to normal how do I get rid of the blinking (Short of pouring gas and lighting....)?

 

Disconnecting the module as described should do it. But quite honestly, it has been years since I've even seen a rear-wheel anti-lock system. Seems to me it should not be flashing if you haven't jumped terminals A to H in the diagnostic connector.

chowderhead72 Enthusiast

chowderhead72

Posted
  • Author
Posted
Now suppose I did miscount and I got a speed error now that the speedo is back to normal how do I get rid of the blinking (Short of pouring gas and lighting....)?

 

Disconnecting the module as described should do it. But quite honestly, it has been years since I've even seen a rear-wheel anti-lock system. Seems to me it should not be flashing if you haven't jumped terminals A to H in the diagnostic connector.

 

 

 

 

 

I am almost positive that this truck does not have abs; 8600 gvw.

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
I am almost positive that this truck does not have abs; 8600 gvw.

 

I know of nothing else that would cause the brake light to flash in a pattern like that. Just look near your master cylinder. RWAL (rear wheel anti-lock) has a black module that's about the size of a thin paperback book, and there's a cylinder that sticks out that's a couple inches in diameter and 5 or 6 inches long.

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