quote:

But beware of just raising the amp rating...could cause other electrical problems!

Not really - the current rating is the max the relay contacts can handle. It changes nothing in the circuit.

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Originally posted by Marvin+Doris:
we had a similar problem a couple month ago but on our Regal it was the black oval/round 80amp relay (seen on your picture just to the left of the part you replaced), the battery would not charge. We got a replacement at a electrical store in Nashville for $58 plus $550 for repair of the fuel relay on our Volvo car that quit on a 105F day and $100 for a rental car to get us home, plus another trip to Nashville to pickup the Volvo. Note to all Volvo owners, this fuel relais will quit due to bad soldering.

I'm not sure what model Volvo you're talking about, but I had a fuel pump relay on my 240 that left me stranded multiple times until I tracked down the problem. Replaced it for around $25 and I've never been left stranded in my Volvo since. Also had to replace the overdrive relay in my 240 as well.

It is a 1990 240DL with 210K miles. Never had any problem with the fuel pump before. The bill included 3 sensors and a labor rate of $100 per hour. But you have not much choice 120 miles from home with no toolbox.

I was having a problem with my rear run panel not working, and it turned out to be a solenoid like the one Nick replaced that was the problem. So are all these relays the same? looks like I have 3 in the engine compartment and 1 in the electrical compartment up front. It would be nice to buy one as a spare and have it work for all locations.

Rusty,
If you allow more current to be able to pass thru the solenoid by going to a higher rating, what happens if the bus bar it is powering is not rated for that high of amps? My concern, as it was with Barth I, is that the draw that was added to the bus bar by others (seems everyone that needed electric went to the same hot bus) possibly exceeded the given rating of it. Yea, I could swap in a 100A rated solenoid and have less problems with it, but if the bus was rated for say 90A and everything powered up to 95A draw I was afraid of a bus bar burning up. I could not find the rating of the bus bar. Therefore I choose to stay with the orignal rating.

Putting in an overcapacity relay just provides a safety margin for the relay. If the relay passes 95A (in your example) the relay is NOT the problem - an undercapacity relay that fails due to overcurrent is NOT the solution. Fuses and circuit breakers are designed to deal with overcurrent, relays aren't.

Your example circuit has issues unrelated to the relay.

Agreed! I maybe stated my comment wrong. What you said is exactly what I was referring to. Just because you put a higher capacity solenoid in place does not mean you have "fixed your problem". Electrical problems happen all the time (blown fuses, tripped relays, etc...) because folks just splice into something (mostly available hot wires) without regard to the overcurrent protection rating.....

http://www.harger.com/products/idx.cfm?subc3id=124
The above company makes conductor anti corrosion compounds that eliminate the high resistance caused by mating conductors and terminals and are especially helpful in our coaches. You might try this as a cure and preventative.

Nick:
I went to NAPA for a solenoid, asked for the ST 85 as you purchased and was informed that they would recommend a solenoid by Cole Hersee as was rated for continuous duty. They informed me that the ST 85 was rated for 80% duty. Price was only a couple of dollars (Canadian of course) more that the ST 85 and came in at $41 plus tax (GST). Amp rating was stated as 100 continuous. Will let you know how it performs in a few weeks time.

Does anyone know the answer to Jerry's question about whether the same solenoid is spec'd or acceptable for the other locations?

Bud

Based on my research the Continuous Duty 80 - 100 amp will function anywhere an intermittant duty relay will work. I would check the manuals in the Barth for the amp ratings and use the highest one for all applications. The fuses will protect the downstream equipment. If the circuit is not protected you would probably draw full battery amps and the higher amp relay would pass the current while the intermittant duty would burn out.

I need to talk to my Napa guy about that Cole Hersee relay. If I can go to 100A rating in the same dimension relay (so it fits in the same place as the ST85), it may mean less time between replacing those. I know I am not the only one here that has replaced that relay in the electrical compartment multiple times. That is why I carry one with me all the time. I thought my Napa guy said the ST85 is rated for continueous duty. I always thought that they just seem to go bad over time because they just are not built to last at the duty they need to perform....

This is the relay we use: http://www.colehersee.com/home/item/cat/174/24115/. It is rated at 85 amps (the coach is 50 amp service) and the starter is well within this rating. The important part is that the relay is fully insulated so you do not have the coil getting its ground through the case, as is the method used on the Ford Starter relays people buy at auto parts stores. On my coach the relay has the ignition switch wire and a ground wire. You hook them up and then the heavy cables to either side and it will carry 85 amps continually, which is the case while the coach is running or whenever the ignition switch is in Run or Start position. You can buy these on Amazon or a large number of online sites.

As you look through their catalog I don't see any 100 amp rated continuous duty relays. It appears only the 24 and 36 volt relays exceed 85 amps.

quote:

You hook them up and then the heavy cables to either side and it will carry 85 amps continually, which is the case while the coach is running or whenever the ignition switch is in Run or Start position. You can buy these on Amazon or a large number of online sites.

The relay that failed energizes the 12 VDC to the house circuits. It's not affected by the position of the ignition switch (at least on my coach).

I believe this same solenoid powers the hot bus bar off of the ignition switch in most diesel Breakaways. It is located in the outside electrical compartment below the drivers window. Reading on this site and having experienced the same trouble, it seems this solenoid fails which then shuts off the bus bar which then shuts off your coach and does not allow it to start. With me, it usually would intermintally fail giving you warning it is going to go bad. I had gone down the road in Barth I and had to put the coach in neutral and try to start it on the move because of this failure. I have read on the site where others pulled over to get their coach started. This is why I carry one with me all the time and recommend it to others with the same set up. I do not know why this solenoid fails and have not found an answer on this forum, but they do. This is why I mentioned the problem of the draw on this solenoid in my postings here. I thought that maybe items that were added to that hot bus in the compartment caused it to draw more than the solenoid would hold up to over a period of usage over time, therefore causing it to fail. This is also why I said I would be interested in a solenoid that was rated for 100A rather than 85A. My thought would be that it would fail less if it was rated higher. The one in Barth II is starting to make me feel it may be going bad. First sign...coach does not start when turning the key first or second time. When this happened to Barth I, we thought the key switch was worn or going bad. Changed that and same problem. That's when I did a search on this site and found others that pointed to the solenoid. Changed that and it fixed my problem, though only for a few years. I had to replace it again right before I sold Barth I. I explained this situation to the new owner and advised him to carry a spare. I still do and will carry a spare solenoid. And yes, I see in Barth II that this same solenoid is used in a few applications throughout the coach. All the more reason to carry a spare!