1998 4700 Brake pressure light ? - TheDieselGarage.com
Thread Details Posted by imported_curbguy, this thread has received 8 replies and been viewed 6644 times.

 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 01-22-2007, 02:39 AM Thread Starter
Junior Member
 
Join Date: Dec 2006
Posts: 9
Points: 564
Thanks: 0
Thanked 0 Times in 0 Posts
1998 4700 Brake pressure light ?

Hello, I just purchased a 98 4700 with 466e motor and a 6+1 trans. It has juice brakes and the brake pressure light comes on after 20 min. of operation. If I turn the truck off and on again. It goes out then comes on shortly thereafter. I don't notice any difference in brakes, they seem good. Truck has 111k on it and I just don't know enough yet to know where to start looking. Any help would be appreciated. Thanks in advance. John
imported_curbguy is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 01-23-2007, 01:44 AM
Senior Member
 
Join Date: Jan 2007
Posts: 3,754
Points: 19,356
Thanks: 0
Thanked 4 Times in 4 Posts
You need to start checking pressures. We had a few trucks w/intermittent brake prssure lites. We never fixed them and never lost brakes but dont like having drivers tell ou that tthe light comes on. Boss says as long as you still got brakes dont worry about it . It only takes one time they dont work to make a heck of a mess.

1996 Gmc k2500 4x4 6.5 turbo diesel, with mods Blew the head gasket, put all new heads, valves, injecotrs gaskets etc on the truck only to get it together and find out it had no oil pressure, and sounded horrible (pry a spun bearing). SOLD
2007 chevrolet 2500hd Duramax loaded. GM LEMON BUYBACK
2007 Chevrolet LBZ 1 ton crew cab 8ft box
on star, xm, tow mirrors, 145 amp alt,
#23 Singles Club
thejdman04 is offline  
post #3 of 9 (permalink) Old 01-24-2007, 01:10 AM
Working 24/7
 
Join Date: Jan 2007
Posts: 44
Points: 6,959
Thanks: 0
Thanked 0 Times in 0 Posts
I had the same problem with my truck. If you go here. http://www.bscparts.com/pdfs/hydromax.pdf and you'll see in the first pic [integral flow switch]. I just had to replace the switch and it stopped. I cant guarantee it but it worked for me. Its a very cheap part at the I.H. store and they should have it in stock. I have also seen the ignition switches cause problems to. They get hot at the back of the switch and it melts the big connector that plugs into the back. Just remove the switch and inspect the back of it.
Tow man is offline  
post #4 of 9 (permalink) Old 01-24-2007, 03:55 AM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2006
Posts: 9
Points: 564
Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for the tips!

Thanks, I will try this tomorrow and see if we can fix it. I noticed that the fluid is about 1" below the cap ring. Isn't it supposed to be up to the ring? I will try fluid first and then check the other items you mentioned. Thanks again. This forum is a great resource. John
imported_curbguy is offline  
post #5 of 9 (permalink) Old 01-24-2007, 12:56 PM
Fire App. Mech.
 
Join Date: Aug 2005
Posts: 982
Points: 29,406
Thanks: 0
Thanked 45 Times in 39 Posts
The fluid will always drop as the pads wear but as long as there is a good amount in there it will perform the same. You should never have to add any during normal use, that indicates a leak. I flush them out with new fluid from time to time and always fill to the top after a brake job (I buy loaded calipers so I lose the fluid that is in the old ones).

Birken
Birken Vogt is offline  
post #6 of 9 (permalink) Old 02-08-2007, 01:42 PM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2006
Posts: 9
Points: 564
Thanks: 0
Thanked 0 Times in 0 Posts
98 4700 brake pressure light

Well we changed the sensor, all the fluid is up and went to back out of the shop and the light and buzzer came on. Shut truck off for 5 min. started and no buzzer or light. Drove 15 miles and no buzzer or light. Went to back up and you guessed it, buzzer and light on. It seems to only be coming on when I back up. Does anyone know if it could be due to the fact that it is a cab/chassis that only has the brake lights and turn signals hooked up, that could cause it to trip somehow? I can't think of any other reason for it to happen. It only comes on in reverse. :shrug:
imported_curbguy is offline  
post #7 of 9 (permalink) Old 02-08-2007, 04:10 PM
Senior Member
 
Join Date: Jan 2007
Posts: 455
Points: 18,263
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via AIM to Docluv2577 Send a message via Yahoo to Docluv2577
a good cause for that light to come on for no apparent reason can be from brake switch issues the brake switch is a 2 part switch it recieves power from two sources and sends power out from each side of it .

check to see if both sides of the switch have 12 volts to them with no brake applied then check that both outputs get 12 v with brake applied if that checks out ok then another possiblity is back feed of power thru tail light or even reverse light circuits verify the tail lights have a good solid ground to them and that the lights are properly wired in

84 f 250 ex cab 4x4 w/92 7.3 ATS turbo 3 in exhaust no muffler K&N filter pumped tweaked 25%
Navistar Diesel electronics specialist( mechanic..lol) 19 years at local dealer
Photos of The Beast

DOC
Docluv2577 is offline  
post #8 of 9 (permalink) Old 02-10-2007, 12:16 AM
Super Moderator
 
John_G's Avatar
 
Join Date: Dec 2008
Location: Tyler, TX
Posts: 4,247
Points: 49,254
Thanks: 101
Thanked 406 Times in 347 Posts
Bad grounds in the brake/tail/back-up lights WILL cause the Brake Warning light and buzzer to activate for no apparent reason.

Reason: The brake circuit does not have a blocking diode in it to prevent "backfeeding" of electricity due to an open or partial ground circuit in the rear lighting circuits.

Cause: Loss of good ground allows electricity to "back feed" from another circuit sharing the same ground as the BRAKE lights, into the Brake Warning Module. The module detects ONE brake signal, but not two, and illuminates the warning light and sounds the alarm. The module is designed to do this as there are two seperate brake switches, and it thinks one has failed.

This is VERY common.

'93 F-250 HD, 7.3L IDI, 5spd - FARM TRUCK
I Support: Trailer brakes an every axle over the towing vehicle's GVW; CDLs for RVers; Safety inspections for ALL vehicles and 6 axle trucks (97K GVW proposal).

Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote - Benjamin Franklin

I vote for LIBERTY!
John_G is offline  
post #9 of 9 (permalink) Old 02-11-2007, 06:29 PM Thread Starter
Junior Member
Threadstarter
 
Join Date: Dec 2006
Posts: 9
Points: 564
Thanks: 0
Thanked 0 Times in 0 Posts
98 4700 brake pressure light

Thanks to all that gave feedback, I did get my flatbed installed and wired and you were right. The warning light and buzzer do not come on at all. Simple fix, and a little more knowledge gained. Thanks again. John :thanks:
imported_curbguy is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TheDieselGarage.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome