Heavy duty solenoids

Special Fred · 10-09-2016, 11:31 AM

So I've had my '89 E350 shuttle bus for a month and have yet to get it to start. The previous owner said that it is an electrical problem and most likely one of the heavy duty solenoids used by the coach company that built the bus. It would seem that the ignition, lights and multiple other systems have been rerouted through a panel built into the outer body of the cab, near the main passenger door. I plan to replace all of the solenoids and circuit breakers in this panel plus a few more in the engine bay as a preemptive strike and to be able to cross those items off the list of potential causes for the no-start condition.

My issue is that I cannot tell the difference between a continuous duty solenoid and an intermittent one. Additionally, I have no idea which solenoid correlates to what specific system, not do I have any idea what the capacity of said solenoids are or need to be. The battery itself is fully charged, connections are good there and at the chassis ground as I did those myself (replaced a pair of clamp on terminals that literally pulled right out). I have also replaced the ignition relay with a known working unit. Bridging the terminals on the solenoid creates noise/action from the starter area so I do not suspect the starter or the ignition relay to be at fault.

I should note that the previous owner did a real number on the steering column. He attempted and subsequently botched an ignition switch replacement which I fixed. However the column itself is very wobbly around the "tilt" area of the steering wheel, which this van may not even have that option. This looseness causes the rod to not properly engage the ignition switch.

One more thing. Whenever the battery is connected, the Check Engine light is on. I have read that this may be an indication of weak current leading to the ECU or possibly some other current-carrying issue. Any insight on these issues would be much appreciated.

Brad_SwiftFur · 10-09-2016, 11:45 AM

I would not think the coach builder would have altered Ford's electrical system for the engine. You didn't say which engine this bus has, but it's either the 7.3 diesel, or one of Ford's gas engines.

As I recall, Ford used a separate starter relay/solenoid for a number of years, which I recall being under the hood for many models. Some also used an ignition relay/solenoid. I forget if/when Ford switched to not using them. I'd check those first. The last Ford van I had developed a strange symptom - it would not start, no gauges, no engine power at random times - and occasionally, once started, it would not shut off when the key was turned off (and even removed!) The ignition solenoid had developed a tendency to stick - both off and on. A sharp tap would unstick it. After replacement, the symptom vanished. I've had several Ford engines that also had starting issues (took several tries before the starter would engage), usually traced to the separate starter solenoid/relay. Usually a sharp tap (while attempting to start the engine) would sometimes do the trick.

Goooood luck.

Special Fred · 10-09-2016, 12:16 PM

My bus has the 351W gasoline engine. As mentioned, I did replace the ignition relay (solenoid, whatever you want to call it) with at least two other good known to be working units all with the same result. I believe the problem is that the S terminal on the relay is not getting a signal. Simulating this signal by bridging the two main terminals produces noise/action from the starter area which I also mentioned.

The factory electrical system has indeed been modified by the coach company. There is a molded-in panel built into the side of the body specifically intended to house a fairly complicated set of relays, solenoids and circuit breakers. There are no batteries in the engine bay; only one large one mounted to a drawer on the bottom of the bus near the passenger door. When I try to start the van by turning the key, I hear a loud click from this panel, not from the engine bay.

cadillackid · 10-09-2016, 02:47 PM

the lpoud click from that basy is the heavy duty accesory solenoid kicking on... that is what powers all your fans, heaters, interior lights, etc...

that is or should be a continuous duty solenoid..

that means your key switch does work.. and likely the ignitiuon circuit is not bad or have a blown fuse.. as that is fed from the same feed..

on a ford, usually on the firewall is another solenoid.. that is the starter solenoid and is a cycle-dity solenoid... usually two big wires going to it and then a ground and then a smaller wire..

you should have 12 volts All the time from the BIG wire going to the battery and ground.. and then when you have someone hold the key in the start position you should get power from ground to one the smaller non-ground wire.. that should "click" that solenoid and provide power to the Other thock wire..

inside the van, when you start from lock.. and turn to Key on tyou get the click in the driver panel... then when you go to the start position you likely get another click in the driver panel which is probably that solenoid releasing.. as all the accessories are cancelled to save battery power for the starter... .

typically the coach builders add a bunch of their own stuff into the driver panel and there is a connector going from the original ford electrics into that driver panel..

USUALLY the ford wiring for the starter is not run through that driver panel... the ford starter solenoid on a van if i remember right was on the fender or firewall under the hood and should be easy to spot..

-Christopher

cowlitzcoach · 10-09-2016, 07:43 PM

IIRC, the vintage of your E-350 had a starter solenoid relay mounted on the radiator core support towards the curb side.

With the key off you should have juice on the big lead on one side of the relay. When the key is turned to the start position it should send a signal to one of the small wires on the relay. When the relay is activated you should then have power on the opposite side to the other large lead that goes down to the starter to energize it.

On my two 1990 E-350's I had a continual problem with that relay misbehaving. I kept a jumper wire handy in order to jump across the terminal when the key wouldn't make the relay energize.

I am trying to visualize the panel you describe. If you could post some photos or at least let us know who made the bus body we might be better able to diagnose the problem.

sdwarf36 · 10-09-2016, 11:46 PM

If the PO screwed with the column, check the neutral safety switch. Move the shifter around with the key in start.

Special Fred · 10-10-2016, 09:28 AM

Thanks for the replies. I am well aware of the Ford ignition relay/solenoid, where it is and how it works. As I have mentioned several times, I replaced it twice and keep getting the same result. I have reason to believe that it is not getting a 12V signal when the key is turned which I also mentioned. I have yet to get someone who can help me turn the key while I test the wire to be sure.

Posting pictures is nearly impossible for me since I have no internet connection and must do everything from my phone. It seems that this website can only handle thumbnail sized attachments (if that) and linking to an outside source is extremely difficult with this phone. I'd have done so already if I could but I guess I'll keep trying. Not sure what a picture of the panel will accomplish without a knowledge of what systems the components inside are assigned to but if it will help then I'll see what I can do. The bus was built by the National Coach Corporation.

For now I just want to know how to tell the difference between a continuous load solenoid and an intermittent one. It stands to reason that only continuous units would be used but I need to be sure. I also need to find out what kind of capacity they should have since several kinds are available. I want to replace all the solenoids and circuit breakers in the panel as well as the engine bay as there are a few more in there.

What I do not understand is why the Cneck Engine light is illuminated as soon as I connect the battery. I did move the column around while trying to start the van.

jazty · 10-11-2016, 08:15 AM

I've had both intermittent and continuous duty solenoids in my hand before. I didn't notice any way to discern the difference except for the labels which clearly identified them. Latching solenoids are a different story. They're easy to tell due to a protrusion on the front.

You could grab the stamped model # off of the solenoids in question and search the internet. That'll tell you real quick.

cadillackid · 10-11-2016, 08:23 AM

and it definitely makes a difference... an intermittent duty solenoid will burn up after an hour or so turned on continuously...

most of the continuous ive seen are rasted at 100 amps, whereas ive seen intermittents uopwards of 300..

-Christopher

family wagon · 10-11-2016, 06:33 PM

As cadillackid alluded to, the electromagnet coil in a solenoid dissipates heat. In their construction, the difference in continuous and intermittent duty solenoids is likely to be some combination of two things: the continuous duty is usually designed to manage/endure heat better, and it may have circuitry inside so that the coil receives a higher current initially to pull the contact and then receives a lesser current to continue holding the contact and reduce its heating. Like jazty wrote, apart from a label, usually there's no outward indicator of which type a particular solenoid is.

Whether a specific application demands continuous or intermittent duty depends on how long the solenoid will be on and how long it'll be off (the "duty cycle"). If it'll be on all the time, or much of the time, or has to operate in a hot environment, it'll likely need to be a continuous duty type.

Special Fred · 10-11-2016, 07:48 PM

After removing one of the high capacity solenoids, I studied the entire thing over to be sure about any markings that may be on the outer body. The only markings on the whole thing are as follows,

"BAT" next to the terminal that is connected to the battery or 12V constant

"12V" stamped on the bottom, pretty straightforward

a lone numeral "7" stamped into the bottom with an engraving die

the number "8921" stamped onto the bottom with ink

No other markings appear on the solenoid(s) whatsoever. The solenoids have a metal bracket spot welded to the body with no rubber shielding leading me to believe that this is the "unshielded" type therefore making the body grounded.

Tootalltechie · 10-12-2016, 05:43 AM

A way to test the lead to and from three key is to use a 12 volt bulb with long leads so you can see it.

Sent from my SM-T530NU using Tapatalk

somewhereinusa · 10-12-2016, 07:31 AM

If the relays were added by the body manufacturer, I doubt if they use intermittent duty solenoids. If the loads are the same you can replace an intermittent with a continuous, not the other way around.

Quote:

I want to replace all the solenoids and circuit breakers in the panel as well as the engine bay as there are a few more in there.

I question why you feel the need to replace all of your solenoids? They rarely go bad. At most I might carry a spare or two. Circuit breakers don't wear out and for that matter are rarely even tripped. In 50 or so years of working on all types of vehicles, about half of that for a living doing electrical troubleshooting, I have seen very few solenoid failures, most of those were the old Ford fender mounted starter ones that carried a heavy load. I think one maybe two bad circuit breakers in all of that time.

If your bus came with a lift of some sort, there are all kinds of switches and relays so that the bus can not be started unless that lift is fully retracted. Many also have switches so that the lift can not be deployed unless things aren't "Just so". Many had to even have the parking brake engaged.

When trouble shooting a no start, get down to just the basics needed to run, per the chassis manufacturer wiring diagram, in your case an '89 E350. If you aren't going to use all of that other stuff just eliminate it.

Dick

Special Fred · 10-12-2016, 12:43 PM

Quote:

Originally Posted by Tootalltechie

A way to test the lead to and from three key is to use a 12 volt bulb with long leads so you can see it.

Sent from my SM-T530NU using Tapatalk

Great tip, I'm going to try this.

Special Fred · 10-12-2016, 12:59 PM

Quote:

Originally Posted by somewhereinusa

If the relays were added by the body manufacturer, I doubt if they use intermittent duty solenoids. If the loads are the same you can replace an intermittent with a continuous, not the other way around.

I question why you feel the need to replace all of your solenoids? They rarely go bad. At most I might carry a spare or two. Circuit breakers don't wear out and for that matter are rarely even tripped. In 50 or so years of working on all types of vehicles, about half of that for a living doing electrical troubleshooting, I have seen very few solenoid failures, most of those were the old Ford fender mounted starter ones that carried a heavy load. I think one maybe two bad circuit breakers in all of that time.

If your bus came with a lift of some sort, there are all kinds of switches and relays so that the bus can not be started unless that lift is fully retracted. Many also have switches so that the lift can not be deployed unless things aren't "Just so". Many had to even have the parking brake engaged.

When trouble shooting a no start, get down to just the basics needed to run, per the chassis manufacturer wiring diagram, in your case an '89 E350. If you aren't going to use all of that other stuff just eliminate it.

Dick

I also believe that the coach company would not have used the intermittent type. Fortunately I found a decent place to get the solenoids, at $15 a piece times four it isn't so bad of an investment into peace of mind. I do not doubt you when you say that these components rarely fail. However, I do not have the experience that you do and so it is my intention to cross off all the potential causes of the issue. Getting back to basics on this vehicle would mean un-modifying the coach builders modifications; which would be moving in the opposite direction that I intend to go. The key start electrical signal is clearly being rerouted instead of going straight to the ignition relay as it originally did; since the click sound originates from the solenoid panel. The bus does not have a lift, so that is ruled out of the equation. I think the member who mentioned a faulty neutral start switch may have been onto something. Those things are cheap, and I'm more inclined to replace small inexpensive items before I inevitably move onto unwrapping and retracing the wiring harness for breaks. Another huge issue is that I do not have a clue what solenoid or circuit breaker pertains to what system...this is why I am replacing them all, because I don't know what I want to delete from this bus yet, if anything at all.

family wagon · 10-12-2016, 01:13 PM

Working without assistance, you could put the ignition key in the run position, turn off unnecessary things like blowers, headlights, etc, and then walk around and jumper from +12 onto the control terminal on that starter solenoid.

Running with the belief that the starter solenoid control input isn't getting powered, you could pick up an inexpensive wire tracer tool and trace back from the starter end of the control wire to see where it goes. A cheap wire tracer goes for US$25 on Amazon; use is as simple as hooking up alligator clips from the tone generator box to your subject wire, then waving the non-contact probe over insulated wires, terminals, etc to figure out whether they're electrically connected to the point where the tone box is attached. This would allow you to trace the wiring harness with a minimum of disassembly.

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