30 amp compressor fuse problem

[92landyacht]

I have a 1992 AS LY 36' motorhome on a P30 chassis. A couple days ago I found that the compressor for my rear airbag system was not coming on. I was able to trace the problem down to no power feed from the fuse block to the solenoid input. The solenoid is engaging. Just no power going to it to power the compressor. I did temperarily use some jumper cable to jump between the battery terminal and the input to the solenoid. This is just to get me moving again. I later found that the ACCESSORY power feed at the upper right corner of the fuse block was melted and the connection was intermittent. The 30 amp fuse that feeds it was still in good shape still.



Trying to come up with a good way to correct this. I could tap into the "CB" feed but the male plug that is currently used is too melted to reuse again. Haven't been able to fine a replacement that can support 30 amps.


One option I'm considering is to tie a line in directly from the battery to feed the solenoid with an inline 30 amp fuse. The original system used a switched 30 amp feed but I don't see a problem with a direct feed since the solenoid is switched as well.


Any issues with my solution? Any ideas on the best way to correct this problem would be greatly appreciated. Any sources for the power feed connector? 10 gauge wire feed with inline fuse?

[mayco]

I think most folks who redo and upgrade their compressor system on the p30 chassis run a direct to battery feed to power the compressor. Using an inline fuse. That's what I did when I replaced my compressor and have had 0 problems since. The OEM wiring is pretty undersized IMO. I think I used #8 agw wire since my compressor is pretty far away from the battery on my 310. Sounds like you're on the right track. I also installed a VAIR combo relay/pressure switch. It's all enclosed, weather tight, and very easy to wire. The relay is still switched from the ign circuit.

[92landyacht]

So basically you're saying to forget trying to tap back into the fuse block and go straight to the battery feed with an inline fuse. I'll look into the VIAIR pressure switch/relay combo as that would update my system and put two components into one. Which VIAIR switch did you choose. I'm looking at the 90110 (85 PSI On and 105 PSI OFF) and the 90111 (110 PSI On and 145 PSI Off). Don't think I need the higher pressure one though since the system seems to run between 45 and 70 PSI depending on load.

[mayco]

Use the 85/105 for sure. Yes, that fuse block is old, brittle and suffered through lots of heat through the years. Go direct to the battery with an inline fuse as you say. The ign circuit will then only have to power the relay, minimal amps minimal heat. You've got the right idea. Pretty easy project on the 310, don't know what your access is like on the LY.
You'll like the install on the combo sw/relay. It's marked well and easy to install.

[92landyacht]

Thanks for your input Mayo. Already ordered the inline fuse and I have 10 gauge wire. I'll be sourcing out the VIAIR pressure switch/relay. The best deal I've found so far is on Amazon for $19.95 with free shipping to Prime members.



The compressor is a little over 4 feet away from the battery on the passenger's side so no issues there. Never really liked high current loads on the switched side of the ignition.



How did you mount the switch? Does it come with any mounting hardware?

[mayco]

Hehehehe, it looks like some piece of strange art work! But I am limited to a space on my 310 that's only about 9" wide so that's why I had to configure it this way. I assembled it on the bench and attached it to a piece of 1x8 treated lumber, then made it so the whole unit can slide out to do any maintenance. It's located in the rear outside compartment on the 310.

Added the quick connect so I can attach an air hose for tires, front suspension, etc.

[rmkrum]

Seen (and perpetrated) far worse plumbing lash-ups. Don't look at the plumbing behind my master bathroom sinks at home. Builder did NOT put in a 2x6 wall for the plumbing, and I have several handfuls of copper elbows and short pipes to get around the drain and vent line back there. It's a good thing its well hidden.

Just be sure to support the pipes close to the quick-connect fitting so vibration does not break off the fitting on the pump cylinder head. Actually the longish piping will help cool the air as it passes through the pipes. I assume the elbow feeds to the pressure tank...me, I'd have used some flexible piping from the finned fitting on the compressor to the rest of the parts to make alignment easier and isolate some vibration, but ya do what ya gotta do to make it work right...

[malett]

I have had several fuse blocks fail over the years, including the main disconnect 100 A block in my home.


The clips and fuses oxidize over time causing heat and the clips to slowly lose their temper and tightness. This compounds the heat and causes the insulation to melt or burn. The fuse will not blow because it does not have an over current condition. Usually the smell of plastic or Bakelite burning is the first clue.



The suggestion of using a direct fused lead from the battery is a excellent fix, but check all the other fuses and blocks. Chances are you will find others that have lost their tension or are corroded.