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HELP! DAC downhill Assist Control Keeps Flashing

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Old Nov 2, 2013 | 04:28 PM
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Exclamation HELP! DAC downhill Assist Control Keeps Flashing

Hi,

I know how to activate the DAC, read the manual, it says shift to L, put in D, and press the DAC button. Keep it under 15 MPH and when you let go of the brake and gas it will maintain the speed, by engine breaking and breaking.

Here is the problem, followed the directions and the DAC light keeps flashing and the truck speed keeps on climbing no slowing down.

What should I look for?

Thank you in advance and have learned a lot about my 2004 GX.
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Old Nov 2, 2013 | 06:41 PM
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If it's flashing the DAC system is not engaged yet. If you've done everything below something maybe wrong w/ your DAC system.

  • Transfer case in 4wd L
  • Transmission in D or L / 2nd gear
  • Going downhill under 15mph press the DAC button
  • Once the light is solid, not flashing, let your foot off of the brake and or gas
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Old Nov 2, 2013 | 07:44 PM
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Originally Posted by RCsGX
If it's flashing the DAC system is not engaged yet. If you've done everything below something maybe wrong w/ your DAC system.

  • Transfer case in 4wd L
  • Transmission in D or L / 2nd gear
  • Going downhill under 15mph press the DAC button
  • Once the light is solid, not flashing, let your foot off of the brake and or gas
Thanks RC,

I have waited for the DAC light to stop flashing and it wont stop. I have tried it in San Francisco on hilly street. Just trying to see what is usually or typically wrong with the system. I have searched google and there are others as well with same issue, someone wrote the switch under the L N H could be faulty and not sending the signal to ECU. Not sure about that, because when the truck key is ON position it runs diagnostic and the DAC lights up and goes away with most of other lights.

I hope Man777 can read my post, he may have a solution.
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Old Nov 3, 2013 | 08:23 PM
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To me it looks not a faulty, but just the system to activate has not been in sequence. Or probably the fuse is out.
First Disconnect your battery ( - Negative ) , wait for 5 minutes, Reconnect. Just turn your Ignition Start key to ACC and wait for a minute and then start your truck, if the flashing is still persistent, then Go the Fuse Relay box at the Driver Footwell area which is Relay box 2 , which basically has the fuse for the instrument cluster DAC First inspect if the fuse is ok if not have it replaced. It is mentioned as Gauge which is 7.5A ( no 11 slot ) have it replaced with the same ampere. let us know your outcome.
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Old Nov 3, 2013 | 11:19 PM
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Mann777,

I was hoping you would read my post. Thank you for the detail instructions. I will do this first thing in the morning and will post the outcome.
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Old Nov 3, 2013 | 11:37 PM
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One more thing I like to add: the light only flashes when the DAC button is pressed, L position and D on the console. If the switch is in off position there are no lights flashing.

I will try out your recommendation and post result.
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Old Nov 4, 2013 | 05:37 AM
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Originally Posted by gxman1
One more thing I like to add: the light only flashes when the DAC button is pressed, L position and D on the console. If the switch is in off position there are no lights flashing
That's why I doubt it's a fuse.
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Old Nov 4, 2013 | 08:31 AM
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Mann777,

Just finished doing the steps you suggested. Still the same issue.

Recap: The light stays off, until gear in L and shift it to D, afterwards press the DAC switch and continues to flash. I have taken it for a ride for several minutes still keeps flashing. Recently I tried in San Fran hill and still flashes and picks up speed.

By the way I also saw in Fuse box 1 there is relay or something with DAC written on it, I didn't touch that I just followed your instructions for fuse box 2.

Thanks
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Old Nov 4, 2013 | 09:29 AM
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Originally Posted by RCsGX
That's why I doubt it's a fuse.
RC,

Searching for this I came across 120 forum;

"There is some sort of switch on the L part of the box that tells the ECU that you are in Low and allows the ABS business to control the descent. My guess is that the switch is knackered, disconnected or something like that. Have a rummage around the T 'box and see if you see something awry there. If the 'box is in H the same flash is visible so my guess is the 'switch bit' is not quite right somewhere."

Anyone knows or have the pages from service manual how do I go about checking this?
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Old Nov 4, 2013 | 09:37 AM
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Originally Posted by gxman1
RC,

Searching for this I came across 120 forum;

"There is some sort of switch on the L part of the box that tells the ECU that you are in Low and allows the ABS business to control the descent. My guess is that the switch is knackered, disconnected or something like that. Have a rummage around the T 'box and see if you see something awry there. If the 'box is in H the same flash is visible so my guess is the 'switch bit' is not quite right somewhere."

Anyone knows or have the pages from service manual how do I go about checking this?
I have the shop manual downloaded but I have no clue what that person is trying to say.

What box are they referring too?

I'm attaching the DAC wiring schematic if that helps you any.....
Attached Files
File Type: pdf
ABS, TRAC, VSC, DAC and HAC.pdf (116.4 KB, 1296 views)
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Old Nov 4, 2013 | 09:57 AM
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Thank you,

What he is saying is.. the L N H Lever above the shifter has switch. Since the DAC does not work in H and flashes. DAC only works when it is in L position, so there has to be a switch indicating it is in L position.

Originally Posted by RCsGX
I have the shop manual downloaded but I have no clue what that person is trying to say.

What box are they referring too?

I'm attaching the DAC wiring schematic if that helps you any.....
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Old Nov 4, 2013 | 10:21 AM
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Originally Posted by gxman1
Thank you,

What he is saying is.. the L N H Lever above the shifter has switch. Since the DAC does not work in H and flashes. DAC only works when it is in L position, so there has to be a switch indicating it is in L position.
Maybe this will help.
Attached Files
File Type: pdf
L4 Signal Pickup Malfunction.pdf (83.3 KB, 4143 views)
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Old Nov 4, 2013 | 11:42 AM
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Originally Posted by RCsGX
Maybe this will help.
Thanks RC, not sure I understand all of it, will figure it out.
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Old Nov 4, 2013 | 01:32 PM
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Originally Posted by gxman1
Thanks RC, not sure I understand all of it, will figure it out.


Check out ih8mud ---> 120-Series

There's a lot of guys that offroad their GXs and they probably know a lot about the DAC system. Maybe start a post there if all else fails.

Keep us posted one way or another.
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Old Nov 4, 2013 | 02:09 PM
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Thanks RC,

By the way really appreciate you helping many members here including myself. I just signed up here, but reading the forum for a while.




Originally Posted by RCsGX


Check out ih8mud ---> 120-Series

There's a lot of guys that offroad their GXs and they probably know a lot about the DAC system. Maybe start a post there if all else fails.

Keep us posted one way or another.
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