Brake Warning Light - E-350 2005 6.0 PSD
Hi everyone....
Here are the symptoms / Ford E-350 2005 SD 6.0. Mysteriously, the brake warning light have come on. This is the light that comes on if you leave the parking brake on. I tried setting the parking brake and releasing it, and sometime (it goes away), or it goes away on its own, The vacuum pump (brake booster) was replaced a year ago, so unless it sprung a vacuum leak, it is unlikely to be the source of the problem. Brake fluid levels are fine (no decrease), and brakes work fine. The only thing might be a slight squeak --- the brakes lining were apparently in good shape as of 2 months ago. A visual check of the brake master cylinder did not reveal a loose wire, nor did jiggling the connector on the underside help. The light goes out by itself.... and may come back on... So what do I do next? What is the proper diagnostics routine? Thanks |
The emergency brake is strictly mechanical, ie; cable actuated. Therefore, my opion again, I would be looking for a switch in the parking brake assembly. That is the way the older units worked and if I didn't have access to a wiring diagram that is what I would be looking for. Good luck.
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Thanks for responding...
My first action was to put WD 40 on the switch... and failing that. I am going to bridge the contact (indicate parking brake off) and see if the light goes away... Thanks again. |
If the wd doesn't work, try a contact cleaner. Nothing to lose. The switches that I have changed were a PITA.
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Well, thanks for the info... I suspected the parking brake switch right away.
It is located right at the parking brake pedal assembly --- very exposed to weather, etc. I had to replace the flasher, it was working but slow (intermittently fail) most likely because of corroded contacts both external and inside from lots of road salt and moisture. The entire metal pieces inside (the anti dive bolster, etc.) are rusted... What I am going to do is to pop a new switch in and see if the problem goes away--- the switch is cheap. If that doesn't work, it is onto the switches at the master cylinder. |
The switch on the master cylinder works on press. The parking brake has nothing to do with that. My op. just don't want you chasing shadows.
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Aye, the question is does that master cylinder switch turn on the brake warning light if there is a problem with the master cylinder?
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no its only a fluid level sensor so low fluid or a malfunction with the sensor or wires to / from
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Which leads me to think the top suspect is a bad emergency brake switch.
Thanks for responding... |
Originally Posted by gearloose1
(Post 8160092)
Which leads me to think the top suspect is a bad emergency brake switch.
Thanks for responding... |
More symptoms
OK,
Intermittent on and off brake light remains --- it will come on and off even with the motor running and vehicle not moving. Sometimes, the use of the parking brake will seem to "wake" it and kill it, sometimes, it doesn't --- no rhyme or reason to it., I am moving suspicions away from the parking brake switch because the chime (warning chime) doesn't come on when the light lights, but definitely does when I hit the parking brake. Is there a control module somewhere? Time to find bad contacts. |
Update:
The instrument panel cluster light on the RPM gauge (left gauge) intermittently goes on and off. Is it possible that there is a light back there on a tether that have fallen down and is now lighting up the warning light? Note: ABS (Yellow) warning is NOT on. Only the RED (I)(P) Waring light. ======================================= Here is a similar case? My 1997 Ford F250 brake warning light stays on w... - JustAnswer Question My 1997 Ford F250 brake warning light stays on with a "P" and "I" under the light. The brake pedal when breaking is very hard which means? Submitted: 1050 days and 19 hours ago. Category: Ford Value: $9 Status: CLOSED + Read More Optional Information Posted by carguy1 1050 days and 19 hours ago. Info Request Do you have gas engine? 1050 days ago. Reply Reply to carguy1's Post: No a turdo diesel 4WD Posted by Blue Oval Certified 1050 days ago. Answer Hello, here is a picture of the cluster i found online. I am researching more information and will post more soon. If you find this information helpful, please click " ACCEPT " . graphic View Full Image Instrument Cluster The cluster warning lamps are located in two vertical columns, one on each side of the instrument cluster (10849), and also along the bottom of the instrument cluster. F-Series optional instrument clusters have the warning lights along the right-hand side and bottom of the instrument cluster. Base Cluster, F-250 Heavy Duty, F-350 and F-Super Duty Item Part Number Description 1 — Fasten Safety Belt Indicator (Part of 10849) 2 — High Beam Indicator (Part of 10849) 3 — Charging System Indicator (Part of 10849) 4 — Turn Signal Indicator (Part of 10849) (RH) 5 — 4x4 High Range (Part of 10849) 6 — Low Range Indicator (Part of 10849) 7 — Turn Signal Indicator (Part of 10849) (LH) 8 — Brake Indicator (Part of 10849) 9 — ABS Indicator (Part of 10849) 10 — Check Engine Indicator (Part of 10849) Posted by Blue Oval Certified 1050 days ago. Answer Here are some more items to check. Also it would be helpful to know if it is only the red brake lamp or both the yellow and red. Brake Warning Indicator Always On Low brake fluid level. ADD fluid, CHECK for leaks and BLEED system as required. Ignition wiring routed too closely to fluid level indicator assembly. REROUTE wiring as required. Damaged float assembly. SERVICE or REPLACE as required. Shorted light circuit. CORRECT short in warning circuit. Worn or damaged brake fluid level indicator. REPLACE brake master cylinder reservoir. Leak in brake system. SERVICE leak. Parking brake engaged. RELEASE parking brake. REFER to Section 06-05. GO to Pinpoint Test B. PINPOINT TEST B: BRAKE WARNING INDICATOR ALWAYS ON B1 CHECK PROPER FUNCTION OF BRAKE WARNING INDICATOR WHEN RELEASED Key on or in ACCY. Verify parking brake is fully released. Is the red brake warning indicator on? Yes No GO to B2 . Brake warning indicator bulb and circuits are functioning properly. B2 CHECK BRAKE FLUID LEVEL IN BRAKE MASTER CYLINDER Check the brake fluid level at the brake master cylinder reservoir. Is the brake fluid level within specification? Yes No GO to B3 . CHECK for leaks in the vehicle brake system and SERVICE as required. FILL the brake master cylinder reservoir to the required level. REPEAT B1 . B3 VERIFY FLOAT BUOYANCY Remove the brake master cylinder filler cap from the brake master cylinder reservoir. Using a clean steel implement, attempt to push the float down. Does the float move down? Yes No GO to B4 . REPLACE the brake master cylinder reservoir. BLEED the brake system. REPEAT B1 . B4 CHECK REAR ANTI-LOCK BRAKE SYSTEM (RABS) MODULE Key off. Disconnect RABS module harness connector. Key on. Does the brake warning indicator turn on? Yes No RECONNECT RABS module connector. GO to B5 . REPLACE anti-lock brake control module. RECONNECT RABS module connector. REPEAT B1 . B5 LOCATE CAUSE OF RED BRAKE WARNING INDICATOR ON Key off. Disconnect the fluid level switch harness connector from the brake master cylinder reservoir. Key on. Does the brake warning indicator turn on? Yes No Diesel only: GO to B6 . All others: GO to B7 . GO to B8 . B6 LOW VACUUM SWITCH CHECK (DIESEL ONLY) Key off. Disconnect low vacuum switch harness connector. Key on. Does the brake warning indicator turn on? Yes No GO to B7 . RECONNECT all loose connections. REFER to Section 06-07B to diagnose reason for low vacuum switch actuating the brake warning indicator. B7 PARKING BRAKE SWITCH CHECK Key off. Disconnect parking brake switch harness connector. Key on. Does the brake warning indicator turn on? Yes No LOCATE and SERVICE short to ground in Circuit 977 (P/W), 640 (R/Y), 531 (DG/Y), or 162. RECONNECT all loose connections. REPEAT B1 . REPLACE parking brake switch. RECONNECT all loose connections. REPEAT B1 . B8 BRAKE WARNING INDICATOR TEST NOTE: The brake warning indicator should only light when the ignition switch is in the START position or when the ignition switch is on and the parking brake is applied (gasoline), or when the vacuum is low (diesel). Release parking brake. Check brake fluid level in brake master cylinder reservoir. Fill as required. Key in ACCY or on. Does brake warning indicator turn on? Yes No CHECK switch wiring for possible short to ground. SERVICE or REPLACE as required. GO to B9 . GO to B10 . B9 MASTER CYLINDER FLUID LEVEL SWITCH WIRING CHECK Partially drain the brake master cylinder reservoir. Key to RUN and observe brake warning indicator. Does the brake warning indicator illuminate? Yes No FILL brake master cylinder reservoir. Switch OK. CHECK for open in fluid level switch to brake warning indicator wiring. SERVICE as required. If no open found, GO to B10 . B10 MASTER CYLINDER LEVEL SWITCH CHECK Manually push the float in the brake master cylinder reservoir to the bottom. Key to RUN and observe the brake warning indicator. Does the brake warning indicator illuminate? Yes No REFILL brake master cylinder reservoir. Switch OK. GO to B11 . B11 FLUID LEVEL SWITCH CHECK Key off. With the fluid level switch harness connector disconnected, jumper between Circuits 512 (T/LG) and 531 (DG/Y). Key on. Does the brake warning indicator turn on? Yes No LOCATE and SERVICE short to ground in Circuit 512 (T/LG). RECONNECT all loose connections. REPEAT B1 . REPLACE brake master cylinder reservoir. BLEED brake system. RECONNECT all loose connections. REPEAT B1 . Posted by Blue Oval Certified 1049 days and 23 hours ago. Answer One more thing with the assistance of " baddad1 " you may have a bad vacuum pump. Low vacuum will turn the red brake lamp on and make the pedal feel hard to push. 1049 days and 1 hours ago. Reply Reply to Blue Oval Certified's Post: I still need to know what the P and the I under neath the warning light means Accepted Answer Hello, i pulled an instrument cluster from a 1997 F250. The " P " and " I " you are referring to do not have lights behind them. The lights you are seeing are bleeding over from the brake lamp which is directly above them. Read more: My 1997 Ford F250 brake warning light stays on w... - JustAnswer |
Update:
As mysteriously as it came, today, it is gone. Update March/ 2010 The light flashed on once again. Brake master cylinder reservoir has a sensor that senses fluid level. Pulling out the plug reveals a long white plastic thing that runs all the way inside the reservoir. It looks like a position sensor that is sensing fluid level inside the reservoir. Took it out, cleaned it.. cleaned contacts. If the brake light flashes on again.. chances are.. it is the master cylinder experiencing the first sign of failure. |
Problem solved.
Photos will be posted when I get around to it. No. 1 issue is a bad vacuum hose and an improperly secured 90 degree elbow joint connector at the brake booster. This caused a vacuum leak and slightly elevated brake pressure, but tripped the vacuum warning switch. No. 2 problem --- a mildly failing master cylinder. The pedal will gradually "leak" to the floor if pushed down hard. Letting off the pedal and re-pumping will bring it back up. Classic sign of master cylinder failure. It is not setting off the brake fluid level light because the "leakdown" is not drawing fluid. However, it is bad. Air in fluid is ruled out because system is regularly serviced (fluid drained and refilled with fresh). On the schedule to have the master cylinder replaced post haste. Update on the update: The 90 degree connector to the brake booster had somehow, wore out the rubber seal on the brake booster. It no longer seals tightly. A huge glob of silicon seal is now on it. Update on the update on the update; A distribution block connects a thin (1/16 or so inch thick) vacuum line to the main wiring harness that goes across the crowl of the E series. It ends in another connection to another thin vacuum line. Apparently the second line (which is not protected) is pulled / kinked. Pushed it back in, and whoa... light went out.. and stayed out. Lesson: follow the think vacuum lines to where it goes --- and find kinks in the line. |
Fixed it
It turned out to be very simple. I was low on brake fluid. I need to figure out how that is happening because I’ve never seen it happen on any vehicle I’ve ever owned. That said, I’m glad it was alerted to the problem before it was too late. It is a very easy to fill the fluid reservoir up and watch the dashboard alert go away. |
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