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1990 ABS Light

Justin Fleming

Justin Fleming

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It appears that the brake light is giving me a flash of 6. Trying to under stand how to read the flashing count it might be a 66 code. Either way I am unable to find what the code is.

Any help would be appreciative...
 
Justin Fleming said:
It appears that the brake light is giving me a flash of 6. Trying to under stand how to read the flashing count it might be a 66 code. Either way I am unable to find what the code is.

Any help would be appreciative...
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The system definetly is flashing six times and continues to repeat the 6 flashes....Any ideas....
 
You are having cruise issues as well, since that is all tied into VSS, if speedometer is messed up, might be what the issue is. If the code is 36, would point towards VSS as an underlying issue.

I assume the ABS codes are flashed the same as the ECM codes? Can't hear the words, but looks like a code 12 first (which is normal...one flash, short pause, two flashes in quick succession, long pause, repeat 3 times) then a code 15. Didn't watch further. Just as a visual as to how the ECM codes are read.

Obviously not going to get the code 12 for ABS.
 
He should have a code 12, 13, 14 or 15 on depending on if the brake pedal is pressed or not and if it is 4wd or 2wd.

If the ABS light is on when he accelerates and he gets a code 6 but both the cruise and the speedometer are working then he likely has an issue with the wiring between the DRAC and the ABS module. I'd start searching right at the module itself, I've seen corroded connectors there before.

Make sure you verify the operation of the brake switch input to the ABS module. It uses two different inputs, one hot while the brake is off and one hot while the brake is applied. If both inputs are off or both inputs are on at the same time it will set a soft code and activate the ABS warning light but will turn it off when you slow down below 15 mph. I chased that one around on my 93 Blazer for a while last summer haha!

You can perform motor tests by hooking up and unhooking the jumper which shows the diagnostics codes. It'll roll over a little bit each time.
 
Russell said:
He should have a code 12, 13, 14 or 15 on depending on if the brake pedal is pressed or not and if it is 4wd or 2wd.

If the ABS light is on when he accelerates and he gets a code 6 but both the cruise and the speedometer are working then he likely has an issue with the wiring between the DRAC and the ABS module. I'd start searching right at the module itself, I've seen corroded connectors there before.

Make sure you verify the operation of the brake switch input to the ABS module. It uses two different inputs, one hot while the brake is off and one hot while the brake is applied. If both inputs are off or both inputs are on at the same time it will set a soft code and activate the ABS warning light but will turn it off when you slow down below 15 mph. I chased that one around on my 93 Blazer for a while last summer haha!

You can perform motor tests by hooking up and unhooking the jumper which shows the diagnostics codes. It'll roll over a little bit each time.
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Help me out a little here.... My cruse control is not working so that I still have to chase down. Right now with the key out the ABS is always flashing 6 times and never stops.

What are you reffering to motor test and hooking up a jumper?
 
Oh, you're not intentionally checking your codes? That's not good...

Is the speedometer working? If not, you need to replace your vehicle speed sensor in the transmission or transfercase depending on if 2wd or 4wd. If that doesn't fix it you need to make sure the voltage signal is making it to the DRAC under the dash. If so, make sure the DRAC is properly powered and grounded. If so, replace it.
 
Russell said:
Oh, you're not intentionally checking your codes? That's not good...

Is the speedometer working? If not, you need to replace your vehicle speed sensor in the transmission or transfercase depending on if 2wd or 4wd. If that doesn't fix it you need to make sure the voltage signal is making it to the DRAC under the dash. If so, make sure the DRAC is properly powered and grounded. If so, replace it.
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Ok the spedo is working great, what is the DRAC module where is that located? Is that the shinny silver box on the bottom side of the steering column? If not what is that shinny box just for reference later...how do I check the voltage signal....
 
The shiny box on the bottom of the steering column is the wiper delay module.

The DRAC module is in a clear or yellow plastic case about the size of a wallet under the center of the dash near the turn signal flasher.

You'll want to see 12V on the pink / black wire, solid (0.2ohm or less) ground on the black / white wire and between 10 - 100VAC across the two input wires from the VSS on the transfer case. It think those wires are purple and green.
 
Russell said:
The shiny box on the bottom of the steering column is the wiper delay module.

The DRAC module is in a clear or yellow plastic case about the size of a wallet under the center of the dash near the turn signal flasher.

You'll want to see 12V on the pink / black wire, solid (0.2ohm or less) ground on the black / white wire and between 10 - 100VAC across the two input wires from the VSS on the transfer case. It think those wires are purple and green.
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Can you describe when I should be seeing these voltages or measurements? Is it just with the key on or when initiating the cruse buttons
 
Pink wire - 12V with ignition on, start.

Green & purple - AC voltage which increases with speed. I am not sure what speed relates to what voltage as it is the frequency which is measured by the DRAC rather than the voltage.
 
If your speedo works, the DRAC works, at least on the speedometer output. It's getting power and ground.
 
dyeager535 said:
If your speedo works, the DRAC works, at least on the speedometer output. It's getting power and ground.
Click to expand...

Spedo does work, so we know we have ground and power, what would be your next methotical approach to trouble shooting this...
 
I'd be checking the wiring between the cruise control module and the ABS module back to the DRAC. If I recall correctly there is one speed signal wire running from the DRAC to each. Without a scopemeter you won't be able to see the signal but you can definitely check the resistance across the wires to make sure they are not open, grounded or exhibiting high resistance.

Before you get into that though... You have checked all your fuses, right?
 
Well I was using the link provided earlier where I didn't see a code 6, so is it really a code 6, and what does code 6 mean?
 
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