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pierrem · 04-03-2010, 03:23 PM

Sorry, I meen relay "K".
This is what I reffer to a battery isolator.
Battery isolator 48525 and 48530 from Cole Hersee Company
Hope the link works.

subford · 04-03-2010, 04:34 PM

I do not think the battery isolator has anything to do with your problem.
What that is doing is disconnecting the house (coach) battery from the chassis (engine) battery when you turn the key to the start position. Its purpose is to charge the house battery as you drive. It has nothing to do with engine cranking. What I thought you were talking about was a battery disconnect for when the motor home is parked.

Your problem could be the neutral safety switch or the ignition switch.
You need to have someone at this point to hold there hand on the start relay "K" while the key is turn to the start position and see if the start relay clicks.
Let us know if it clicks or not and then we can help you some more.

pierrem · 04-04-2010, 12:56 PM

I just had someone turn the start swich while I was holding the start reay "K" and no clicking sound nor any vibration.

Pierre

wa8yxm · 04-04-2010, 02:24 PM

Are you sure it is a battery isloator that is clicking and NOT the starter solenoid?

Ford used to use a starter solenoid that was mounted other than on the starter, in appearance (And for that matter funciton) it is identical to some makes of battery isolators... (There is a major difference, you can not interchange them, since the starter solenoid is designed to operate for nor more than 30 seconds to a minute tops, then burn out.. Where as a Isolator needs to operate for many hours... But in appearance they are identical, Well, some are)

Common issues that cause that

Bad connection, battery-solenoid or solenoid - starter

Bad starter

Locked starter

And a sufficently dead battery

Oh, and a bad solenoid (of course) I actually had to override one of those one day for some folks who were seriously worried.. Short story

A carpet cleaning company was trying to get a contract.. So they had wetted down the carpet in the School Board meeting room and when they turned the key to start the Wisconson V-4 powered super-vacuum what they got was CLICK, and nothing else.. No Rrrrr Rrrrr Rrrrr Varoom.. Just Click

Bad solenoid

Thankfully I happened to walk by,, And fairly quickly bypassed the bad solenoid so we got the desired sound effects.. And a nice strong Vacuum to suck the water (And dirt) out of the carpet.. Alas, they did not get the contract.

They also did not get sued for damages so they were rather happy with me.

pierrem · 04-04-2010, 06:52 PM

wa8ymx, I'm sure it's not the starter solenoid because it's mounted on the starter and no sound is coming form it when the ignition switch in turned. Also I was able to start the motor by connecting a cable from the battery to the starter solenoid.

Pierre

subford · 04-04-2010, 07:37 PM

OK now pull the "K" relay out.
Using a 12 Volt test light check between ground and socket pin #86 when someone turns the key to the start position.
The test light should light while the key is in the start position.
Let us know what happens.

/

pierrem · 04-05-2010, 09:36 AM

I don't have a 12 Volt test light (I can go buy one if needed) but I used my volt meter. When the ignition swich is off I get 12.8v from socket pin #30 and none from #86. When the switch in turned on I still get 12.8v from pin #30 and still none from #86.

subford · 04-05-2010, 12:41 PM

That would mean you have a problem with the "Sensor assembly digital transmission range" or the "Ignition Switch".

It could be that your shifter on the column is bad or the "Sensor assembly digital transmission range" is bad. In other word it does not think you are in Park or Neutral or it is a bad switch.

Digital Transmission Range (TR) Sensor:
The digital transmission range (TR) sensor is located on the outside of the transmission at the manual lever. The sensor completes the start circuit in PARK and NEUTRAL, the back-up lamp circuit in REVERSE and a neutral sense circuit for GEM control of 4x4 low engagement. The sensor also opens/closes a set of four switches that are monitored by the powertrain control module (PCM) to determine the position of the manual lever (P, R, N, (D), 2, 1).
Some call this the MLPS.

The ignition switch is mounted below the steering column and is activated using the ignition key and rotating the ignition switch lock cylinder on the steering column.

pierrem · 04-05-2010, 02:36 PM

Wow! great information subford, thanks.
I will start by buying a new switch and go from there since it sounds less complicated to change than the Sensor assembly digital transmission range.

Pierre