Anyone know where the headlamp relays are located in a '94 Breakaway? There is one that is labeled "headlamp relay in the electrical compartment ahead of the left front wheel but it controls the tail lamps from the headlight circuit.

I am getting 10.3 volts thru the headlamp circuit on low beam and jumps to 12.8 volts when the high beam is pulled.

Thanks

It's not what you asked for but do yourself a favor and try this anyway.

Try measuring the voltage on the low beam circuit when your on high beam - then reverse and take voltage readings again on the opposite circuit then what your on. This will tell you how good your ground is to the headlight circuit.

Do these reading with the ground probe attached to a very good ground - do not use the ground wire at the headlight plug!

If your getting low voltage readings and your using the ground circuit at the headlights your only checking half of what you should be. I think you'll find (like mine) that there is some voltage bleed over. This is caused by a weak ground wire and or connection.

Bill N.Y.

I agree with Bill N Y - but anyhoo, my headlight relay is on the lower left of the steering column, but mine's got a bunch of GM wiring - the headlight relay is really a mechanical switch. I doubt that's the way yours is, and it's doubtful the issue is the relay anyway.

Check the ground circuit.

I measured all the voltage at the lights and used the ground connection from the battery and various places along the frame. I did not use the ground at the lights.

I am looking for the voltage drop along the low beam circuit and as such, the ground MUST be perfect or at the battery which it was.

This is a Sparton chassis and has most of the wiring connections available in the electrical box just ahead of the front wheel. With the engine off I measure at the ignition relay 12.6 volts with the meter grounded at the battery. There are ground strips in the electrical box and I measure the same voltage from the ignition relay to those grounds.

When I measure the HDLP wire (this is the headlight master power lead)or the HD low beam wire at the barrier strip with low beams on, I get 8.8- 9.0v, when I pull the high beams on, this voltage jumps to 12.2v. There is a 3 volt drop somewhere in the low beam circuit. This is NOT a ground issue. I am not measuing the voltage at the head lights or using the ground wire at the lights but when I measure the voltage at the head lights, using the same grounds at the battery, I get the same readings.

I know where the high beam realy is but if there is a low beam relay, I haven't been able to find it. If there isn't then it probably is in the steering column switch. The voltage to and from the light switch is almost battery voltage and doesn't change high or low beam.

One other thing, the low beam voltge is interupted when the high beams go on. That is why I mentioned the main head lamp main voltage is changing depending whether low or high is on. Obviously it isn't load because there is more load when the high beams are on but the voltage is higher.

Still looking.

If you have an electrical relay system (as opposed to my mechanical switch) you may actually have two headlight relays - one to power the headlights, and a second to switch between high- and low-beam. This accounts for the interruption of the low beam when the high is engaged (and vice versa).

I know you're asking other Barth owners that have a Breakaway for advice on location - I can't directly answer your location question. I don't want to step all over your thread but I would like to ask some more questions. If this doesn't help you out then maybe someone else might benefit. (besides, I want to break out that 5 pole relay diagram I made up a while back )

Is the "incorrectly labeled" relay a 5 pole relay like what is pictured below?

What happens when you take the relay out that is labeled "headlamp relay"?

Does all 4 of your headlights come on at high beam? Just two? Which ones?






I know you know this...

Most of the time voltage comes from the headlight switch and goes to pin 30 when you turn on the headlights. When your on low beams the relay is at rest. Power should naturally flows from pin 30 to pin 87a without doing anything. Once you pull in on your high/low beam switch that switch grounds out and the small coil inside the solenoid pulls down on the contacts and gives you your high beams.

You stated "the low beam voltage is interrupted when the high beams go on" If the lights go out and then come back on when going from low to high beams then it should be a 5 pole changeover relay like what is pictured above. This is good news, these things make clicking noises. Have a helper operated the high/low beam switch and listen for it to click. Have your helper use slight pressure so you don't hear the clicking of the switch.

Let's face it, the relay has got to be between the headlight switch and the headlight. I know I just stated the obvious, I'm not trying to insult you as I know your background. Lucky for us Barth owners that's a very small run. Behind the dash - under the dash - behind the front sheet metal.

I work on every make and model of tractor trailer trucks and this is how I usually find a relay. Now if the relay doesn't work (not in this instance) then I back feed the circuit and look to see what is hot at 87 or 87a with all of the relays removed.

In many cases for me if I can find one relay then the entire relay bank is located very close by.

Bill N.Y.

quote:

Is the "incorrectly labeled" relay a 5 pole relay like what is pictured below?

What happens when you take the relay out that is labeled "headlamp relay"?

Does all 4 of your headlights come on at high beam? Just two? Which ones?

1.)Yes, The the relay is a SPDT.

2.)The tail/clearence lights go off, nothing else.

3.) The outer lamps are low/high beam lamps and the inner are high beam only. When high beam is selected, the low beam filament goes out in the outer lamps and the high beam filament goes on in the outer lamps, along with the inner lamps (high beam lamps). So, in other words, in high beam all four lamps are lit but the low beam filament in the outer lamps are off(which is common practice).

Does anyone have a chassis wiring diagrahm for the Sparton chassis that I could get a copy of?? Would be very helpful!

Thanks

On my Breakaway, there's an oblong hatch on top of the dash on the driver's side, and several of the relays (IGN, headlight, etc.) are there on mine.

There has got to be another relay (or switch) for switching from high to low beam (dimmer switch). As I mentioned, on my GM-powered Breakaway, it's a mechanical latching switch on the side of the steering column, similar to the old foot switches of yesteryear.

If that relay you found is the dimmer relay (as opposed to the headlight relay), then it could be the culprit. Outputs at pins 87 and 87A should be the same when switching between beams; if they aren't, bad contact and replace the relay.

But I suspect it's the headlight relay, not the dimmer, that you found. If the headlight relay is SPDT it would send power to the headlight circuit via pin 87A, and pin 87 wouldn't be used (it's fairly common practice to use a SPDT as a SPST - simplifies inventory). You've confirmed that it's good because the high beams work normally.

Something else would have to switch between beams. That "something else" could even be a mechanical switch inside the combination switch on the steering column (unlikely). Or it may be like mine, a switch on the left side of the steering column operated by a rod from the stalk.

If the stalk has one position for high beam and another for low, that pretty much means a relay as the dimmer switch. If it's cyclical - operate the stalk once for high, again in the same direction for low, it's likely a mechanical switch.

Since you're getting good voltage on the high beams and not the low, your tests have ruled out the ground lead.

So the suspect part of the circuit is the low beam hot lead from the dimmer relay. Either the dimmer relay/switch could be bad, or the connection from the dimmer relay/switch is bad (the more likely cause)

Or there's a short in low beam hot lead. With headlights off and the bulbs unplugged, check the resistance from the low beam hot lead and ground with the voltmeter on its lowest range; this is also unlikely.

A final possibility, also unlikely, is an internal short on one of the bulbs thamselves. With headlights on low, unplug one, see if the other brightens. If not, plug that one in, unplug the other and check.

And I'm purely speculating as you know, since neither of us have a wiring diagram...

quote:

Originally posted by Rusty:
And I'm purely speculating as you know, since neither of us have a wiring diagram...

Interesting observation. I spent my working life chasing rogue or missing electrons, and can read a diagram like most people read a three-word road sign. My bathroom reading used to be wiring manuals. But to be any good at understanding text here, I have to draw a diagram in my mind first. I guess some of us are just more visual than others.

I'm a reformed marine angineer (think ME and EE) and I've also spent a lot of time on electrical (and steam and hydraulic) diagrams...what I find frustrating in vehicles and boats (boats are a lot more straightforward) is not so much how the circuits are laid out, but where are the danged things physically located? We can pretty much troubleshoot by rote, if we knew where the things are that need checking out.

There are no relays in the area behind the dash that I can see find. All of the relays that you mentioned are in the electrical bin ahead of the left front wheel.

Now if for some strange reason Barth (or Sparton) ran the head light lead all the way back to the rear near the engine and then all the way up front again, thatt could account for the large voltage drop. There are bunches of relays in the back which aren't labeled but it would be well to get to know their function also, relays don't last forever.

Dave had this posted back in Sept 10, 2003...

I am trying to develope info on available chassis manuals.
I received the following email back from Spartan Chassis:

Mr.Bowers,

Each manual would be different per chassis, if you could supply the last five digits of the chassis's vechicle identification
number, and contact Spartan's parts dept at
800-722-3025 you could purchase these items.

And Barthmobile member "Rod DeGarlais" answered back on Sept 17, 2003...

I have the original "Spartan motorhome chassis owner's manual" that came with the coach when I bought it. 1993 Barth Diesel Pusher 33BS Vin # 4S7PT9J18PC008226. Model EC-2242 20,000 GVW. I could copy the pages and mail them to you if it would be of any help. There are a few notes made in it by the original owner. I will be in Plankinton, SD for a week around the 25th of October. If you are a pheasant hunter and are out that way I could bring them with me and I will also have the entire owners manual. I plan to pull my pickup (2001 Dodge Ram 1500 diesel). I had the 5.9 Cummins in the MH boosted to 265 hp and am curious how it will do. If not enough I will go back and take it up to 300.
Addendum: I copied the owner's manual and could mail it. Didn't mean the only way you could get it was by coming pheasant hunting.

Maybe Rod DeGarlais still has a copy?

Bill N.Y.

Rod DeGarlais Profile

I have a Spartan EC chassis on my 1993 33' Barth Breakaway. I sent a copy of the Spartan Motor Home Chassis Owners Manual to Dave Bowers back in '03. To get to your problem -- there is no relay for the low beams. I added one in the electrical box on the left front side. I used the wire coming to the low beam post in the box to activate the relay. The light relay in the box is not in line with the low beam. I had around 9 volts to my headlights. Like you everybody says check the ground. The way the coach is wired the resistance is such that only a lower voltage reaches the low side of the sealed beams. If you like I could draw a diagram of what I did and email it to you as I am unfamiliar with attaching a graphics to a post. I bought the relay at Radio Shack because I prefer the English to Bausch.

Thanks Rod!

Would you have a phone number that I could call you? you could email me the number if you don't want to be public about it.
would like to talk about some other issues as well.

Mine is:
(408) 354-0123
and my email is:
ed@mwrench.com

I would love to get a copy of the chassis owners manual, I have one but it only has one page of electrical and only shows some components. if that is all you have then it wouldn't help.

I do know there is about at least 10 feet of chassis wiring harness that is folded up near the electrical box. I think Spartan used one harness for a lot of their chassis and for the 30 ftr just folded up the excess.

Sure is strange there would be tht much voltage loss in their circuit.

Again Thanks for the tip and yes I would like to see your drawing.