Hi guys I am new here and could use a little help... I have a 98 F150 XLT with manual shift on the fly 4X4. 4WD is not engaging when I shift the floor shifter and here is what I have trouble shot so far...

- there is vacuum at the two solenoids on the firewall but there is always power to both solenoids???

- the release side solenoid (Red hose) passes vacumn through and the engage side (Blue hose) does not pass vacumn and neither one changes state if I connect and disconnect the plugs

- when I engage 4WD I hear a click of a relay somewhere (anyone know where that relay is?) but the power to both solenoids remains on all the time

- in testing for power at the vacuum solenoid plugs my meter would read 12V but I tried taping taillight bulbs to the plugs to give me indication from inside the truck but they would not light up (not enough juice?)

- the vacuum actuator on the front axle works fine as I can fool the system and engage the 4WD by jumping the vacuum to either side of the diaphram by disconnecting one side and jumping the other through the right side solenoid

I have read posts about electronic shift on the fly systems which talk of the GEM module grounding out the vacum solenoids so I was wondering if in the manual version the relay I hear clicking is supposed to ground out the appropriate solenoid and does anyone know what the normal state is for the solenoids.....thanks in advance for any info

 

When I had my 97, I chased that same problem forever. I replaced the vac. system with a Posi Lok. Check out this site. It will elimate this problem.
http://www.4x4posi-lok.com/app_ford.html

 

Thanks for the info - that would definitely eliminate the vacuum system altogether.
I was thinking that if I knew how the solenoids are supposed to work I could run them from a switch inside the cab, but if all else fails the Posi Lok looks like the answer - a totally manual system with no chance of electrical failure when you need it most!!

Does anyone know how the solenoids work - should they be powered all the time and shut off when activated (a normally open valve) or vice versa? Thanks again...

 

There is a constant 12 to the solenoids. The GEM grounds the solenoid to activate it. Vacuum is channeled through the bottom nipple to the top nipple to activate the vacuum motor on the axle. When a solenoid is deactivated vacuum at the bottom is blocked and the top nipple is vented to air. This vents the vacuum motor so the other solenoid can pull the motor the other way.
The default setting ground applied to the disengage solenoid. You can test this with a continuity meter. Engage 4x4 and probe the red ground wire to the engage solenoid (closest solenoid to the fender). There should be continuity to ground. Then disengage 4x4 and probe the Gray w/Black stripe ground wire to the disengage solenoid ground wire ( closest solenoid to the engine). There should be continuity. If these circuits check out then test the solenoids. If they don't test OK the 4x4 indicator switch or the relay or the GEM may be defective.

Apply vacuum to the top nipples of the solenoids while the bottom one is blocked.
With with 4x4 disengaged test the engage solenoid. It should not hold vacuum. Then test the engage solenoid. It should be holding vacuum.
Then engage 4x4 and test the engage solenoid. It should not hold vacuum. Then test the engage solenoid. It should hold vacuum.

I would then test the blue and red lines to see if they hold vacuum. They may have a small leak.

.

 

Thanks for the info Jean - I am heading out to the garage to test this all out. By the way I noticed you live in Windsor. I live in the Orillia area and was wondering if you got nailed with lake effect snow in the last storm - they got dumped on just north of me, hence the need to get my 4WD working to haul the sleds around etc....

Cheers

Mark

 

No snow yet. I miss the white stuff.

BTW I have the Posi-Lok cable on mine. Because of my clutch pedal I had to move the routing of it. Now that I worked all the bugs out it works great.

Regards

Jean Marc Chartier

 

Well I think you have helped me solve the problem...

- I did the continuity to ground test and it turned out ok - both plugs were working properly when 4X4 engaged and disengaged

- to test the solenoids I did not have a vacuum pump and gauge so I used a piece of hose that fit tight over the nipples and sucked on it (don't read that sentence out of context ). The engage solenoid (left fender side) tested ok but the disengage (right engine side) was passing vacuum no matter whether 4WD on or not.

- when I removed it I found that it was bulged on the bottom and cracked - could be water had gotten inside and froze and split it. I found out some more info while searching part numbers online. It seems these solenoids have chronic issues with water leaking into them and Ford has updated them....here is the quote from the Lincolns of Distinction website....

"The right solenoid (E8AE-9H465-AA) controls the vacuum to the return side of axle engagement diaphram. The left solenoid (E8AE-9H465-BA) controls the vacuum to the activation side of the axle engagement diaphram. Ford has been having chronic problems with water entry into these solenoids, corroding them from the inside and seizing them,as you've seen!

They've been redesigned and those old part numbers (E8AE-9H465-AA/BA) have been superseded.

The latest designs are listed as:
Disengage solenoid 6L3Z-9H465-A (identified by electrical connector rib at 9:00 position)
Engage solenoid 6L3Z-9H465-B (connector rib at 6:00 position).

The original part numbers are still available, but if you don't want this problem re-occurring, you DO want these new solenoids."

I will be looking to pick up the new updated solenoid tommorrow and will let you know if they work.

Thanks everyone for the help

Cheers and bring on the snow - I'll be ready!!!

Mark

 

Took a while but I finally got it going. I went to the dealer here in Barrie, Ontario and they wanted $80 for the new part ($27 in the US and $80 in Canada - go figure?), so I searched a few wreckers and found a pair in an Expedition for $20 each and replaced the bad one and it worked.

I am also going to make a plastic cover to keep the rain off of the two solenoids as they get constantly dripped on in their location (this is an update on the newer trucks I believe).

Thanks again Jean Marc for all the help

Keeping the rubber side down,

Mark

 

JMC, I dont have any documentation on my truck, could you elaborate on the relay?

 

Same issue here in my 2001 manual shift & manual 4x4 engagement.

I show 12VDC at each solenoid. The position sensor on the transfer case has continuity to ground on the bottom (white) wire pin when 4 Hi is engaged. I do NOT have continuity to ground on any of the 4 wires at the solenoids in any position. Seems odd since the switch at the transfer case seems to be doing it's thing. Possible relay and / or other problem here?

Any ideas? Thinking about replacing both solenoids and sensor, but want to make sure that will work...probably looking at $100 or so.

EDIT: I am going to retest the solenoid connectors this afternoon using actual resistance values rather than simple continuity indicator.

 

Probed the leads at the solenoids with the negative terminal via plated safety pins...here's the data:

Left Side (Engage?)
2WD
red: 7.37k Ohm
wht/blu: 0
4HI
red: 120 Ohm
wht/blu: 0

Right Side (Disengage?)
2WD
gry/blk: 120 Ohm
wht/blu: 0
4HI
gry/blk: 7.5k Ohm
wht/blu: 0

Look right? Seems awfully high while "grounded", but with the pins and all. I even have 4ga. upgraded grounds.

 

Before ordering parts, I checked the linkage at the axle to make sure it wasn't seized. It moves pretty easily, so no worries there as long as the actuator hasn't gone ***** up.

Here are the part numbers for the updated solenoids:

6L3Z-9H465-A
6L3Z-9H465-B
($32 each)

...and the "oil sensor" (check ball switch) just below the vent tube on the Borg Warner 4406 transfer case:

4L3Z-7E440-AB
($19)

Any idea why it would be wet between parts 3 & 4 in this diag?

 

I replaced the solenoids and oil pressure switch last night. The lower backside of both solenoids was cracked with evidence of corrosion in the engage side. My pressure switch wasn't bad, but I replaced anyway after getting a 7/8" deep well and 3/8-1/2 step down adapter so I could use my 3/8" extensions.

I didn't test it out on the street / off road, but I did get under the front end and confirm that the actuator moves then piston in and out about 1/2" total so I'm sure I'm good.

 

97 f150 4.6 manual shift
I have ground to both solenoids (and vacuum from) all the time. It does not try to lock while I'm in 2h but when I put it in 4h or 4l it locks but then won't disengage without removing the 4WD vacuum line. Could this be anything other than a bad GEM?