97 f150 4wd relay location????

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Old 03-09-2009, 04:44 PM
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97 f150 4wd relay location????

was acting up,now it does nothing,does any one know where the 4wd relay is?I checked the fuse panel,the relays under the dash,the relays under the hood and the 2 relay boxes that are under the pass. side dash just above the air bag.are there any more?also there is no power going to the connector that goes to the 4wd switch.would that be the relay too?
 
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Old 03-09-2009, 09:18 PM
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Start with some additional information.

Is it an ESOF, or Manual ?

Which wire did you check to the 4WD mode switch ?

What fuses have you checked ( and how did you check it ) ?

Do you brake lights work correctly ( all 3 )

Have you checked the vacuum solenoid ?

If you have Cruise control, does it work and have you had the recall done ?

When you say you checked the relays, how did you check them ?
 
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Old 03-10-2009, 08:02 AM
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Originally Posted by SSCULLY
Start with some additional information.

Is it an ESOF, or Manual ?

Which wire did you check to the 4WD mode switch ?

What fuses have you checked ( and how did you check it ) ?

Do you brake lights work correctly ( all 3 )

Have you checked the vacuum solenoid ?

If you have Cruise control, does it work and have you had the recall done ?

When you say you checked the relays, how did you check them ?
its an auto,I checked all wires by jumping them and listening for a click.all brake lights work,check all fuses,under dash and under hood.I have cruise control but never worked since I got the truck,I bought it from the original owner.I swapped each relay with a new one I have and still nothing.
do you know what relay the 4wd one is?
 
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Old 03-10-2009, 08:43 AM
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Checking the wire by jumpering them together was not a good idea.

The 4WD mode selector switch is 3 resistance levels that is a single return signal to the GEM. Depending on which resistance ( 360 Ohms, 1.1K ohms or 3.9K ohms ) is depending on which mode the GEM places the truck into.

Checked all fuses ? Why did you check the fuse for the radio ?

If the Cruise control does not work, that could be a problem with the VSS ( vehicle speed sensor ) not allowing 4Lo to work ( speed to high, and the truck will not shift into 4Lo ).

The "relays" for the 4WD mode are in the Transfer case shift relay module. This is 2 SPDT relays, that work together to select only 1 mode.
Sounds like you already found the transfer case electric clutch relay ( even though you swapped it, but did not test it ). This relay is controlled by the GEM.

The GEM also controls both the center axle disconnect solenoids ( mounted on the firewall ).

If you would like to follow some trouble shooting steps ( rather then remove and replace ) here is a thread where the problem was a faulty vacuum solenoid. This is if you have not damage to the GEM by jumpering wires together at the 4WD mode selector switch.
 
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Old 03-10-2009, 10:23 AM
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Originally Posted by SSCULLY
Checking the wire by jumpering them together was not a good idea.

The 4WD mode selector switch is 3 resistance levels that is a single return signal to the GEM. Depending on which resistance ( 360 Ohms, 1.1K ohms or 3.9K ohms ) is depending on which mode the GEM places the truck into.

Checked all fuses ? Why did you check the fuse for the radio ?

If the Cruise control does not work, that could be a problem with the VSS ( vehicle speed sensor ) not allowing 4Lo to work ( speed to high, and the truck will not shift into 4Lo ).

The "relays" for the 4WD mode are in the Transfer case shift relay module. This is 2 SPDT relays, that work together to select only 1 mode.
Sounds like you already found the transfer case electric clutch relay ( even though you swapped it, but did not test it ). This relay is controlled by the GEM.

The GEM also controls both the center axle disconnect solenoids ( mounted on the firewall ).

If you would like to follow some trouble shooting steps ( rather then remove and replace ) here is a thread where the problem was a faulty vacuum solenoid. This is if you have not damage to the GEM by jumpering wires together at the 4WD mode selector switch.
there is power going to the switch cause it lights up(just the switch when I turn the lights on)like I said before when I moved the selector switch to 4h it a relay would some times click 2 or 3 times before the 4l light would come on thats why I thing its the relay.and also the CEL was on also when I bought the truck.I should go get it scanned
 
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Old 03-10-2009, 10:27 AM
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Originally Posted by my97f150207
there is power going to the switch cause it lights up(just the switch when I turn the lights on)like I said before when I moved the selector switch to 4h it a relay would some times click 2 or 3 times before the 4l light would come on thats why I thing its the relay.and also the CEL was on also when I bought the truck.I should go get it scanned
also when I first got the truck both 4h and 4l was working
 
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Old 03-10-2009, 10:38 AM
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If the illumination is on, that is the dash lights. That is not the signal to the GEM working. 2 different circuits.
The status of the 4WD switch is shown on the instrument cluster.

You replaced all the relays ( didn't test them ) so that is not it, unless you cannot say for sure the relays you were using were good ( thus the reason to test the relays, not just remove and replace ).
If it works some times, and not others, that could be down to the vacuum solenoid also. You keep looking for yet another relay to replace, when it could be a mechanical item.
The GEM controls and reads the position of the 4WD system, and reports it back in terms of the 4WD indicator lamps on the cluster.

There is a CEL also, anything else ?

You might want to think about taking it to a shop, and have them work on it.

Your approach to problem diagnoses is a bit scattered, and you leave important information out when asking for help, and are just replacing items, and shorting wires together without knowing what you are doing.

Did you read the thread above, and follow some of the steps ?
 
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Old 03-10-2009, 01:19 PM
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Originally Posted by my97f150207
was acting up,now it does nothing,does any one know where the 4wd relay is?I checked the fuse panel,the relays under the dash,the relays under the hood and the 2 relay boxes that are under the pass. side dash just above the air bag.are there any more?also there is no power going to the connector that goes to the 4wd switch.would that be the relay too?
The no voltage at the switch is normal. What are the symptoms of your problem. And exactly which wires did you short together?
 

Last edited by JMC; 03-10-2009 at 01:21 PM.
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Old 03-10-2009, 01:29 PM
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now for some reason the turn signals dont work but the hazards do and its locked in 4l but the front wheels aint ingauged and no 4wd light is on.
 
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Old 03-10-2009, 01:57 PM
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Originally Posted by my97f150207
now for some reason the turn signals dont work but the hazards do and its locked in 4l but the front wheels aint ingauged and no 4wd light is on.
I suspect your wire shorting procedure cooked the GEM. It may have also burnt a few fuses. That why it is important to know which wires you shorted.....

Regards

Jean Marc Chartier
 
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Old 03-10-2009, 02:05 PM
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well is what I did was started the truck turned the lights on,the power wire for the light on the selector switch.I use that one and touched the other 3 wires on the connector,every time I did it it blew the 5 amp fuse for the light.
 
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Old 03-10-2009, 02:06 PM
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Originally Posted by JMC
I suspect your wire shorting procedure cooked the GEM. It may have also burnt a few fuses. That why it is important to know which wires you shorted.....

Regards

Jean Marc Chartier
also what is the "GEM"?
 
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Old 03-10-2009, 03:27 PM
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Originally Posted by my97f150207
also what is the "GEM"?
Generic Electrical Module, the thing you trashed by randomly shorting wire to it.

The signal return for the GEM for the 4WD mode selector is the same one from the MFS.

Got a good dealer or service garage around ?
 
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Old 03-10-2009, 03:29 PM
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Originally Posted by JMC
I suspect your wire shorting procedure cooked the GEM. It may have also burnt a few fuses. That why it is important to know which wires you shorted.....

Regards

Jean Marc Chartier
JMC,

Does this sound like your "friend" from the MCD race no show ?

I am starting to see a striking resemblance between the 2.

Steve
 
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Old 03-10-2009, 03:29 PM
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so is that why my 4wd isnt working
 

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