Hazard Lights/E40D?
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Senior User
Joined: Mar 2006
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Hazard Lights/E40D?
"To everyone that has a 90's or newer Ford with the E4od transmission.
DO NOT Run your truck with the HAZARD lights on.
By doing so will cook your transmission.
The torque converter lock up solenoid is controlled by your brake lights. Every time they flash they switch the solenoid on/off.
By doing that it ends up destroying your transmission !
Just an FYI for you Ford owners."
This was posted on another forum that I read. Wondering if there is any truth to this?
DO NOT Run your truck with the HAZARD lights on.
By doing so will cook your transmission.
The torque converter lock up solenoid is controlled by your brake lights. Every time they flash they switch the solenoid on/off.
By doing that it ends up destroying your transmission !
Just an FYI for you Ford owners."
This was posted on another forum that I read. Wondering if there is any truth to this?
Lead Driver
Joined: May 2007
Posts: 8,608
Likes: 13
From: Belair md
i have never noticed this before, i will get the converter locke dup and hit the hazzards to see what happens. i would imagine ford was bright enough to wire the hazzards into the brake light switch and not the multifunction switch
Postmaster
Joined: Jun 2007
Posts: 2,795
Likes: 1
From: Rogue River, OR
Me thinks that we need input from the Guru's on the validity of this.
I would not think that Ford would make this kind of Boo Boo and not issue a service correction notice.
It sounds like a wiring mod gone bad. JMHO
Rog
I would not think that Ford would make this kind of Boo Boo and not issue a service correction notice.
It sounds like a wiring mod gone bad. JMHO
Rog
Lead Driver
Joined: May 2007
Posts: 8,608
Likes: 13
From: Belair md
yeah, that would definatly justify a huge recall on fords part. i dont remember ever having this happen and i have driven with the hazzards on several times and never noticed anything odd going on
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,723
Likes: 2,650
From: SE Florida
Originally Posted by c00nhunterjoe
yeah, that would definatly justify a huge recall on fords part.
It IS true. I was there when this was fixed.
What happened is that the torque covnerter unlocks with the brake lights. In the early E4ODs the PCM would see the four way flashers as a brake application. The PCM was just looking at the change in voltage on the brake light circuit and couldn't tell the difference.
The fix was in the calibration. The PCM was calibrated to ignore the brake light circuit once the TPS read more than 10% pedal.
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Postmaster
Joined: Feb 2004
Posts: 3,266
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From: Levittown
Mark
About when was it changed (year).
If you run your hazz lamps the 3rd brake light will not flash with the lower(hazz). The load is not the same 4ways vs brakes.
Bill
About when was it changed (year).
If you run your hazz lamps the 3rd brake light will not flash with the lower(hazz). The load is not the same 4ways vs brakes.
Bill
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Fleet Mechanic
Joined: Aug 2007
Posts: 1,508
Likes: 2
From: The boonies by Dallas OR
Originally Posted by MADVAN
It works off the 3rd brake light.
No effect at all with the hazz on.
Bill
No effect at all with the hazz on.
Bill
Another issue on old trucks with the flasher is that it would pulse trailer brakes too. But when the thrid brake light was added, but the transmission and the trailer brake enable both came from the third brake light circuit and neither pulse when the flashers are on.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,723
Likes: 2,650
From: SE Florida
Originally Posted by MADVAN
About when was it changed (year).
Originally Posted by MADVAN
If you run your hazz lamps the 3rd brake light will not flash with the lower(hazz). The load is not the same 4ways vs brakes.
Posting Guru
Joined: Sep 2004
Posts: 1,096
Likes: 2
From: Ohio
This is TRUE for 1995 and 96 models. its tied into the same cicuit. I had a 95 dually that was this way and my dads 96 was this way. My current 96 is this way as well. i noticed it when I had some trailer issues and tuned them on at about 45 mph and noticed it DID unlcok the TC. I dont know if a manual lcokup switch would get you around this or not.
Fleet Mechanic
Joined: Aug 2007
Posts: 1,508
Likes: 2
From: The boonies by Dallas OR
Originally Posted by Todd525
This is TRUE for 1995 and 96 models. its tied into the same cicuit. I had a 95 dually that was this way and my dads 96 was this way. My current 96 is this way as well. i noticed it when I had some trailer issues and tuned them on at about 45 mph and noticed it DID unlcok the TC.
Here is the schematic from the '95 shop manual (click for big):
I dont know if a manual lcokup switch would get you around this or not.
The torque converter locks in dirve or overdirve when the throttle is depressed and the brake is off. It also locks in first or second if the revs are over 2200 RPM and the throttle is above 3/4 after a time delay - brake on or not BTW.
Last edited by joe_13894; Jan 20, 2008 at 10:34 PM.
Posting Guru
Joined: Sep 2004
Posts: 1,096
Likes: 2
From: Ohio
Nope, it kicks it into limp mode with hazard lights. Drive down the road in OD, click your hazards on and watch your RPMs, they WILL jump. It doesnt show it in this diagram, but it is wired in. I cant remember who posted it, or where they found it.
Do a forum search, youll find it. It was hatched out about a year or so ago on here before.
Do a forum search, youll find it. It was hatched out about a year or so ago on here before.
Cargo Master
Joined: Jul 2006
Posts: 2,756
Likes: 38
From: Nampa, ID
True. I don't think this affects the '97-up trucks. I use my flashers when approaching accidents and law enforcement traffic stops. I haven't noticed my RPMs jumping. I'll have to pay closer attention next time.
