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octanefam · 11-01-2014, 08:48 PM

The one thing that i would really like to get figured out on my 1984 Suncrest MH with the 454 and on the P30. So my gauge cluster that has the fuel, water, and oil presure, etc does not work. Gauges are all pinned to one side or the other. We have checked the fuse once you put a new one in it blows instantly. So let me hear on the places I should check.

Thanks

BFlinn181 · 11-01-2014, 09:26 PM

Blowing a fuse indicates a short. In some vehicles, the instrument cluster is supplied power through a voltage regulator. (limiter) If it's bad it can cause the gauges to read inaccurately.

You might start by removing all the lights from the back of the gauges to be sure none of them are shorting things out. After that, you might un hook all the faulty gauges, replace the fuse and then reconnect the instruments one at a time until the fuse blows. That would narrow things down.

TQ60 · 11-02-2014, 09:20 AM

Replace fuse with a light bulb, use an old light socket with wires and solder the wires to the ends of the blown fuse, and then start disconnecting things.

When bulb goes dim the load changed then repair.

Bulb limits the current and allows you to work with both hands and not fumble with voltmeter or waste a bunch of fuses.

BFlinn181 · 11-02-2014, 09:46 AM

Quote:

Originally Posted by TQ60

Replace fuse with a light bulb, use an old light socket with wires and solder the wires to the ends of the blown fuse, and then start disconnecting things.

When bulb goes dim the load changed then repair.

Bulb limits the current and allows you to work with both hands and not fumble with voltmeter or waste a bunch of fuses.

I like your idea better than mine! Nice thinking.

MattC · 11-02-2014, 11:40 AM

Your symptoms are exactly those of a damaged system. The mentioned light bulb trick is a very good start, but you won't find it be pulling fuses. Something probably damaged the harness, so, look where something moved or crushed wires. even if this happened suddenly, the damage could have been done years ago and the situation finally caused a failure.

Good Luck

Matt

TQ60 · 11-02-2014, 04:06 PM

"The light bulb trick" is only replacing the blown fuse then with the light glowing where you can see it you start carefully exploring looking for the pinched wires which may be issue here.

By unplugging connectors and operating switches things can be isolated quickly.

ONE SHOULD NOT JUST WIGGLE THE WHOLE HARNESS!

You need to gently do things as a short caused be a pinched wire will become not shorted when the harness is moved.

By being real gentle uou can sneak up on it and if you are tugging a harness and the light goes dim you push other way to make it bright.

Then closer inspection.

BTDT many times from pagers to ambulances...just takes time and care...do NOT hurry as you will get frustrated and it may fix itself only to fail later.

leadman · 11-08-2014, 11:01 PM

Also follow the harness and look at the fuse box to see if anything has been added to that circuit that could be shorted.
I have many wires crossing over from the chassis to coach or coach to chassis. The gauge lights should be on a different fuse but one can't rule then out. I have found light bulbs with the element broken on one side and hanging down inside the bulb but were shorted to ground.

Ted Lambert · 01-15-2015, 08:15 PM

It sounds like a problem with a constant voltage regulator. Just Google it and you should find pictures of one.
They are most times located under the dash,mounted on a steel member.
They are quite common in those years. I can't remember just how to test it but they are cheap to buy. One thing I do know is that the new one has to be mounted first as it must be grounded before any wires can be attached or there is a chance of burning out the new one.
I am unable to attach a picture from the I Pad I am using. If you are unable to find a picture let me know I will hit the computer and post a picture.
Are you sure that the fuse you are replacing is related to the gauges? If you turn on the ignition do the gauges pin themselves at max. If they do I believe the problem is the voltage regulator and the fuse issue has to do with something else.
On a lighter note I had a fellow mechanic that had a habit of installing a screw when a fuse would blow. He would sit back and watch for smoke. He got away with this for some time.till one day the rear heater in a sleeper caught fire while he as watching the dash for smoke. lol
Don't do that!
Good luck and keep us posted.