Parking Break Light and Rear Anti-Lock Light On?

WuTang · 03-19-2010, 06:16 PM

I just went out this morning and started her up and I noticed the parking break wasn't on (even though I thought I had put it on), but the light was on and so is a REAR ANTI-LOCK light.
It pulls when it's in drive so I don't think the parking break is stuck.
I looked at this thread, but my breaks don't grind at all...
http://fullsizebronco.com/forum/showthread.php?t=4765
Any ideas?

Runnin'OnEmpty · 03-19-2010, 10:35 PM

Try the simple things first; there should be a parking brake switch
up under the dash and affixed to the parking brake mechanism.
Give it a good spray with WD-40 or something similiar, and maybe
it'll loosen up the sticking switch.

Not sure about the rear ABS light, but maybe the two problems
are connected...

lovinfishin9 · 03-19-2010, 10:54 PM

Check the brake fluid, low brake fluid will cause both lights to be on.

goober · 03-20-2010, 04:29 PM

double that... the under dash switch mentioned above could be doing it as well. first check your brake fluid... If your truck has cruise control have you done the recall yet? The plug on your master cylinder leaks out fluid and can cause a fire... When I found out about the recall mine was smoking all the time from under the hood... close call there...

almost all ford's with cruise control were affected. that's why so many trucks burnt down in people's driveways for a while there.

AKAfactory25 · 03-21-2010, 08:09 PM

a 1988 doesn't have the cruise control switch.

**El Kabong** · 03-21-2010, 11:56 PM

Please excuse the cut & paste. 87-92 Broncos have Rear Wheel Antilock Brakes (RABS). There's a self test routine for pulling RABS codes quoted below, & section "C" below that covers testing when both BRAKE & REAR ABS lights are on. Go thru section "C" first, & it'll tell you if you need to do the self test. It's incomplete at this point, but there's some more info here: Common Replies to FAQs, post 8. If you need more info on another flashout code, let me know & I'll look it up.

Here's a good resource thread with more info from Miesk5 & jermil01: Brake and Rear ABS lights on

Quote:

Pulling RABS Flashout Code. This routine should be good from 87-92.

Quote:

The 90 service manual gives a routine to pull RABS codes. When the light comes on, don't turn the truck off before reading the codes. Put it in park, chock both front & rear of the wheels, note whether the red brake light is lit also, then momentarily ground the test connector.

On my 90, the test connector comes out of a large loom under the dash, coming through the firewall, near the parking brake. On mine there are 2 similar connectors in that area, the correct one has only 1 black wire with an orange tracer running to it, & was hidden on top of the loom. The correct one is hanging down on the bottom right of the 90 pic below. 92 has the test plug on the passenger side. See jermil01's 92 pics below.

After you've grounded & ungrounded the wire, the yellow abs light starts to flash. Count the flashes. It said to not count the 1st series, because it may start in the middle. The last flash of the series is a long flash. Then it repeats over & over, until you turn the key off.

Count all of the short flashes & the long one together (So 4 short & 1 long is code #5). If I remember right, it should be a number between 2 & 15 or so. In Steve83's Brakes & Hubs album, he has the code definitions & other info for RABS-II near the bottom.

There are also more testing instructions in the manual that I can look up after you know what the code is, & whether the red brake light is on or off.

90 Test Connector

Quote:

92 Test Connector

Quote:

Originally Posted by jermil01

92 Module

Quote:

Originally Posted by jermil01

And the RABS module behind the glove box

Quote:

C Testing Procedure from the 1990 Ford Truck Shop Manual. Use this section when both Yellow & Red lights are on.

Quote:

Test C
Yellow ANTILOCK light On and
Red BRAKE Light On

Quote:

C1 -Low brake fluid

Brake fluid level ok = Go to test C2
Brake fluid level low = Check for fluid leaks & repair. Fill system

Quote:

C2 -Master cylinder float -Check float for buoyancy
1- Remove cap from master cylinder.
2-Using a clean steel implement, push down on float in reservoir.

Float moves down = Go to test C3
Float does not move down (Sits at the bottom of the reservoir) = Replace master cylinder reservoir.

Quote:

C3 -Diode/resistor element -Check for proper functioning of the diode/resistor element.
1- Turn ignition key to the on position.
2- Check parking brake & release if applied.

Both ANTILOCK & BRAKE warning lamps go off = Replace RABS diode/resistor element.
Both ANTILOCK & BRAKE warning lamps stay on = Go to test C4.

Quote:

C4 -Diode resistor element continued -Continue to check for proper functioning of the diode/resistor element.
1- Remove the parking brake switch & the diesel low vacuum switch, if so equipped.
Both ANTILOCK & BRAKE warning lamps go off = Replace RABS diode/resistor element.
Both ANTILOCK & BRAKE warning lamps stay on = Go to test C5

Quote:

C5 -Antilock valve switch
-Obtain the flashout code as described in Diagnosis & Testing in this section.
(See the section above for pulling RABS codes)

Flashout code is obtained = Refer to Flashout Codes Charts
ANTILOCK & BRAKE warning lamps stay on steady = Go to test C6

Quote:

C6 -Master cylinder switch
-Check for the proper functioning of the master cylinder level indicator switch.

1- Remove the connector from the master cylinder.
2- Connect a jumper wire between the 2 purple/white wires in the connector.
3- Turn the ignition key to the on position.

ANTILOCK & BRAKE warning lamps stay on = Go to test C7
ANTILOCK & BRAKE warning lamps go off = Replace the master cylinder reservoir.

Quote:

C7 -Brake Light Wiring
-Check for shorts in brake light wiring.
1- Disconnect module harness connector from module
2- Turn ignition key to the on position.

Antilock light goes off & Brake light stays on = Check for short to ground in the 977 circuit. Refer to wiring diagram in this section.
Both ANTILOCK & BRAKE warning lamps go off = Replace module.

wannanotherbronco · 03-26-2010, 08:38 PM

I know this may sound crazy but my rear abs light came on after i changed out my batt. what happened was a plug came unplugged on the neg side batt. cable, the clip was broken and it just kinda slipped out. I just didn't notice it at first plugged it back in and light out!

bestdallasfan6 · 03-26-2010, 10:46 PM

Had this happen to me when i had my parking brake on for a while when i busted a brake line. But what I did was pulled one of the fuses started it, then put it back in and started it again and badabing! Both lights were gone. No idea why it worked but it did.

WILLIAMF · 08-21-2012, 11:12 AM

Got a? What does it mean if just the anti lock light is on and does not go off even momentarily.
The master cylinder is new the brake warning light works with low fluid and parking brake. I'm at a loss here the truck is a 1991 brunco with f350 master booster and wheel cylinder.

mickey556 · 08-21-2012, 01:24 PM

my rear ABS light as been on for years, through parts at it, nothing helped it... Now i read that it could be the low fluid sensor? Heck i disconnected that years ago as the wires were corroded and falling apart... Now i feel slightly dumb.

WILLIAMF · 08-21-2012, 03:55 PM

I've done things like that it works with park brake and low fluild I'm wondering if it isn't the module

inmytree · 08-22-2012, 02:41 PM

Quote:

Originally Posted by WuTang

I just went out this morning and started her up and I noticed the parking break wasn't on (even though I thought I had put it on), but the light was on and so is a REAR ANTI-LOCK light.
It pulls when it's in drive so I don't think the parking break is stuck.
I looked at this thread, but my breaks don't grind at all...
http://fullsizebronco.com/forum/showthread.php?t=4765
Any ideas?

Pull the code(s) as per a previous post....

I had he same issue, RABS light and Parking Brake Light on all the time, no brake grind, and it turned out to be the RABS valve assembly...

I replaced it and the lights are off....

WILLIAMF · 08-22-2012, 03:26 PM

I've. Tryed to pull codes the light just Burns steadily no blink or any thing

4NIC8R · 08-22-2012, 05:21 PM

Williamf
Have you followed the directions in this thread above to perform the self-test and pull codes?

WILLIAMF · 08-22-2012, 06:15 PM

Yes I only have rear anti light on not the brake light

WILLIAMF · 08-22-2012, 06:56 PM

Got it fuse 17 10 amp had no power but ABS was all that didn't work. Does this make any sense?

WuTang · 10-11-2012, 08:28 PM

Since I never did reply to this and state what was wrong, it was something simple and stupid. Bronco needed more brake fluid. Topped off the reservoir, issue was gone.

smptx · 10-11-2012, 10:12 PM

Quote:

Originally Posted by lovinfishin9

Check the brake fluid, low brake fluid will cause both lights to be on.

x2

joeteasley · 02-26-2013, 04:46 PM

My 88 has the same problem but my rear brakes are holding some

**El Kabong** · 02-26-2013, 09:07 PM

That's what mine was doing, dragging the rear brakes.

Are both the Yellow REAR ABS and the Red BRAKE lights on?

03-19-2010, 06:16 PM	#1
WuTang My Bronco Isn't My Only Join Date: Mar 2010 Location: Lake Havasu City, AZ Posts: 1,003 iTrader: (2) Bronco Info: 1988 Ford Bronco 302 AOD\|1993 Ford F-150 302 E4OD	Parking Break Light and Rear Anti-Lock Light On? I just went out this morning and started her up and I noticed the parking break wasn't on (even though I thought I had put it on), but the light was on and so is a REAR ANTI-LOCK light. It pulls when it's in drive so I don't think the parking break is stuck. I looked at this thread, but my breaks don't grind at all... http://fullsizebronco.com/forum/showthread.php?t=4765 Any ideas?
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03-19-2010, 10:35 PM	#2
Runnin'OnEmpty Registered User Join Date: Nov 2004 Posts: 455 iTrader: (0)	Try the simple things first; there should be a parking brake switch up under the dash and affixed to the parking brake mechanism. Give it a good spray with WD-40 or something similiar, and maybe it'll loosen up the sticking switch. Not sure about the rear ABS light, but maybe the two problems are connected... __________________ 1978 Bronco Ranger XLT, Trailer Special with FreeWheeling Package, 351M, NP435, Ford alloys w/BFG 31's, MAC/IMCO hybrid exhaust.
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03-19-2010, 10:54 PM	#3
lovinfishin9 Registered User Join Date: Nov 2007 Location: Waycross, GA Posts: 113 iTrader: (0) Bronco Info: 1991 Bronco XLT 5.0 Stock on 35's	Check the brake fluid, low brake fluid will cause both lights to be on.
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03-20-2010, 04:29 PM	#4
goober Registered User Join Date: Jul 2009 Location: western n.c. Posts: 696 iTrader: (0) Bronco Info: '94 XLT stock 5 speed manual t-case (my 3rd bronco)	double that... the under dash switch mentioned above could be doing it as well. first check your brake fluid... If your truck has cruise control have you done the recall yet? The plug on your master cylinder leaks out fluid and can cause a fire... When I found out about the recall mine was smoking all the time from under the hood... close call there... almost all ford's with cruise control were affected. that's why so many trucks burnt down in people's driveways for a while there. __________________ "when man behaves like a beast he loses the pain of being man" by someone somewhere sometime... '94 XLT stock 5 speed 302
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03-26-2010, 08:38 PM	#7
wannanotherbronco Registered User Join Date: Mar 2007 Posts: 4 iTrader: (1) Bronco Info: 87 Eddie Bauer	I know this may sound crazy but my rear abs light came on after i changed out my batt. what happened was a plug came unplugged on the neg side batt. cable, the clip was broken and it just kinda slipped out. I just didn't notice it at first plugged it back in and light out!
	Nominate Post for Newsletter

03-21-2010, 08:09 PM	#5
AKAfactory25 Registered User Join Date: Nov 2005 Posts: 27 iTrader: (0) Bronco Info: 05 Mustang, Metallic Mineral Grey	a 1988 doesn't have the cruise control switch.
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03-26-2010, 10:46 PM	#8
bestdallasfan6 Registered User Join Date: Nov 2009 Location: Spotsylvania Va Posts: 127 iTrader: (0) Bronco Info: 95 f150 7" of lift and 35s	Had this happen to me when i had my parking brake on for a while when i busted a brake line. But what I did was pulled one of the fuses started it, then put it back in and started it again and badabing! Both lights were gone. No idea why it worked but it did.
	Nominate Post for Newsletter

08-21-2012, 11:12 AM	#9
WILLIAMF Registered User Join Date: Oct 2011 Location: Dothan Al Posts: 17 iTrader: (0) Bronco Info: 1991 EB 5.0 e4od 4WD	Got a? What does it mean if just the anti lock light is on and does not go off even momentarily. The master cylinder is new the brake warning light works with low fluid and parking brake. I'm at a loss here the truck is a 1991 brunco with f350 master booster and wheel cylinder.
	Nominate Post for Newsletter

08-21-2012, 01:24 PM	#10
mickey556 Registered User Join Date: Jan 2012 Location: PA Posts: 493 iTrader: (0) Bronco Info: '89 bone stock. Got 3/4 of parts for spring resto and disel swap tho!!!!	my rear ABS light as been on for years, through parts at it, nothing helped it... Now i read that it could be the low fluid sensor? Heck i disconnected that years ago as the wires were corroded and falling apart... Now i feel slightly dumb. __________________ ** 1989 Bronco XLT - 7.3 idi NA / ZF5 speed conversion underway. Build thread http://www.fullsizebronco.com/forum/...=1#post2865645
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08-21-2012, 03:55 PM	#11
WILLIAMF Registered User Join Date: Oct 2011 Location: Dothan Al Posts: 17 iTrader: (0) Bronco Info: 1991 EB 5.0 e4od 4WD	I've done things like that it works with park brake and low fluild I'm wondering if it isn't the module
	Nominate Post for Newsletter

08-22-2012, 03:26 PM	#13
WILLIAMF Registered User Join Date: Oct 2011 Location: Dothan Al Posts: 17 iTrader: (0) Bronco Info: 1991 EB 5.0 e4od 4WD	I've. Tryed to pull codes the light just Burns steadily no blink or any thing
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08-22-2012, 05:21 PM	#14
4NIC8R Registered User Join Date: Jul 2012 Location: Nevada Posts: 192 iTrader: (0) Bronco Info: 91 Silver Anniversary	Williamf Have you followed the directions in this thread above to perform the self-test and pull codes?
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08-22-2012, 06:15 PM	#15
WILLIAMF Registered User Join Date: Oct 2011 Location: Dothan Al Posts: 17 iTrader: (0) Bronco Info: 1991 EB 5.0 e4od 4WD	Yes I only have rear anti light on not the brake light
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08-22-2012, 06:56 PM	#16
WILLIAMF Registered User Join Date: Oct 2011 Location: Dothan Al Posts: 17 iTrader: (0) Bronco Info: 1991 EB 5.0 e4od 4WD	Got it fuse 17 10 amp had no power but ABS was all that didn't work. Does this make any sense?
	Nominate Post for Newsletter

02-26-2013, 04:46 PM	#19
joeteasley Registered User Join Date: Oct 2012 Posts: 1 iTrader: (0)	My 88 has the same problem but my rear brakes are holding some
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02-26-2013, 09:07 PM	#20
El Kabong Driving Stuff Henry Built Join Date: Oct 2006 Location: Pasadena, CA Posts: 4,212 iTrader: (9) Bronco Info: -90 xlt, 351w, e4od, 3.55:1, sag, warn hubs, trans cooler, 35" bfg m/t, -73, 400, np435, 35s	That's what mine was doing, dragging the rear brakes. Are both the Yellow REAR ABS and the Red BRAKE lights on? __________________ Baba Looey's Favorite FSB Links........................Common Replies to FAQs “Don't find fault, find a remedy.” -Henry Ford
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