inter.wiper not working while in gear but ok in park!!, low range light dimly lit then goes out in about 5 min./ wiper delay works ok while in 4WD.

HELP!!!!!!!!!!!!!!!

 

Could be a loose ground wire somewhere around the dash/steering colum.

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97 Lariet-sc-4.6-4x off road-auto-3.55 LS-
superchip-K&N-3"
pvc air box mod-Granetelli MAF

 

you wont believe this, but its a bad switch on your transfer case causing both problems. Its hard to imagine the xfer case switch can mess with the wipers, but i've been bitten by that same thing at work.(im a ford tech) its the screw in switch that lets the GEM module know whether its in 4wd hi or 4wd low thats bad, also you might want to change your xfer case fluid because water in the fluid is what ford says makes the switch go bad.

 

jeff is partially right.. he is thinking of the Trans range selector switch. However it sounds like there may be aproblem with the GEM itself.

 

no, jeff is totally right, it is not the trans range switch(MLP sensor). It is a bad transfer case switch that tells the GEM if its in 2wd, 4hi or 4low. When the water messes it up, it sends a sig to the GEM that its in 2wd and 4low at the same time, and due to this weird situation that the GEM was never made to expect, the GEM wont work the delay wipers when there is a input for 2wd, 4low, and anything other than park or nuetral all at the same time. And that is excactly how the hotline described it to me about 3 years ago right before the TSB came out on it.

 

by the way, the tsb is 97-11-19 and here is what it says:LIGHT TRUCK: 1997 EXPEDITION, F-150, F-250 LD


ISSUE:
Water may be present in the transfer case on some vehicles. This may cause:

Transfer Case Mode Switch to become inoperative
The 4X4 "Low Range" light to appear dimly lit
The intermittent wipers to become erratic or inoperative
Vehicle Speed Sensor (VSS) Diagnostic Trouble Codes (DTCs) P0500, P0503, P1500, and P1501 to be set.
This may be caused by water splashing into the transfer case through the vent tube assembly, possibly causing the transfer case mode switch to short out, and/or the VSS gear to swell and set the VSS DTCs listed above. Shorting out the transfer case mode switch may cause the intermittent wiper mode to function erratically, as well as possibly causing the 4X4 light to work incorrectly.

ACTION:
Inspect, diagnose, and/or replace the necessary components. Refer to the following Service Procedure for details.

SERVICE PROCEDURE
Procedure for VSS Gear:
Inspect VSS gear in the transfer case for looseness.
Replace Gear (C8OZ-17285-B) as necessary. Refer to Section 308-07B of the 1997 F-150/250 Workshop Manual for removal and installation procedures.

Procedure for Transfer Case Mode Switch:
Check resistance of the Transfer Case Mode Switch.
The resistance of the switch should be at least 100,000 ohms. If it is less, replace the switch (3-Position Switch, E7TZ-7E440-A, manual shift only). Refer to Section 308-07B of the 1997 F-150/250 Workshop Manual for removal and installation procedures.

Procedure for Transfer Case Vent Replacement:
Remove old vent hose from fitting on front of transfer case.
Attach end of new Vent Hose (F75Z-7A246-AA) to fitting, and route the hose up over the top of the transfer case (Figure 1).

 

Jeff - My '88 LD 250's wiper delay has a mind of its own. Delay time can vary significantly depending on truck's mood. Delay variations are independent of the speed. A couple of months ago I timed the longest delay at 21 sec and the next at about 5 sec. A few weeks later the 5 sec delay became about 11 sec. Haven't noticed any other electrical gremlins to date. Any thoughts?

By the way how can us non-Ford techs aquire copies of the TSBs?

 

go to your dealer and ask them to run tsb on oasis for ya there should be no problem