DavidL

So, you have a F53 chassis? If so, then it uses OBDII protocol (what cars use since 1996) Most any inexpensive bluetooth ELM327 based scan tool will work with free / inexpensive app software to get basic diagnostic codes that helps in the majority of engine problem conditions. At the high end, there is GMs TechTools which does all of the GM procedures like what a dealership uses.

You should have the RV weighed for each axle, compare that weight to the tire specific chart which will provide you the proper pressure. It doesn't make any difference what others use. You need to use the pressure for your rig as you have it loaded. The softness of the ride will "be what it is". Don't overinflate, and definitely don't underinflate. If the ride is not nice enough, consider upgrading to Koni shocks. Some tires are softer than others, even when inflated correctly. Other than that, enjoy the ride.

give that bay a nice power wash. Check all cells for correct fluid levels. Like 96 evo, I am betting you have some cells that are drying up.

A new set of noises? On many RVs, dependent on their suspension design type, the RV will creep forward/ backwards when raising / lowering which can make some good scale noises.

You can always figure out which wire is supposed to be wired to power and temporarily wire it to a 12 v power source. Most all of the electric valves also have a manual method to open close the gate. Step1 - figure out what brand the valve is Step2 - get the manual online Step3 - manually drain the tanks which buys you more time to properly diagnose stress free.

RV dash AC is just like auto, just longer lines, less sophisticated control systems and easier access to the parts. Ports are either at the compressor (on the motor) or next to the evaporator or both. If an auto shop wants to, they easily can diagnose / repair / recharge RV dash air. rooftop units are considered generally not serviceable ie: replace them if leak. Are you sure on R410a? Never saw that on an RV. R134 like auto. And we are talking Dash air, not roof air - right?

Like Stephen K states....but...the "upper left"...is this looking at the front ie: passenger side? That is more typical since AC evaporator is normally on passenger side on most RVs.

Possibly remove, clean really well, preheat and braze the corrosion area to restore the cooler if one can't be found. Cast iron is a pain to work with, but it's possible with the right weld technique.

Curious - how did you determine you had an internal leak? Saw oil had water in it (chocolate milk shake?) Saw oil in water? Both? I had to replace my cooler due to collision damage and went to a truck salvage yard and purchased one that was similar but different outlets. I then went to a "AnyHose" supplier of hoses / clamps / adapters and fit up the parts to connect the new cooler. But, I would be surprised if the fix is as simple as replacing the cooler and then...how did the cooler get damaged...mine was a very robust copper unit that looked highly durable. Not sure if you have similar. Post a picture.

Check the tank, not just the overflow. It's possible the tank is low and the overflow is full. Wherever the sensor is, that's the tank that is complaining. If it's a sensor, then, you could bypass the switch, but do that carefully as you wouldnt' then have that as a safety device. You ideally also would have a scan tool to double check why the engine is complaining. A water pump issue will certainly affect the temp (no indication from the OP that the temp was irregular -yet...) But it shouldn't affect a low coolant indication unless the pump leaked the coolant out...

There are specs for the suspension height. So that should be checked. If the sign is dragging, then raise the sign post leveling. The height of the sign is not critical. Suspension height is. I guess if you were really baffled, there are plenty of magnetic wifi cameras you could temporarily mount underneath to see under what conditions is the sign dragging to see if it's of any question.

As part of your diagnostics, I would suggest Picture document all connections to all batteries. Inspect. Clean the battery bay. I use a powerwasher. My OCD gets my powerwasher trigger finger nervous when I see people post pictures of their battery bays. Dry Mark / label all connections Disconnect all Clean all connections and battery posts. Rewash to get rid of any acid laden corrosion. Recharge batteries Test all batteries individually. Replace as needed. Best is always to replace the set so they are balanced. Connect all again. Retest that all is good. The above is just good maintenance that prevents issues that crop up when you are on vacation and not within range of tools / time.

Most vehicles have a code for low battery. And typically it sets multiple codes as each ECU complains and sets it's own code. Odds are, thats all it is.

Like 95 Evo is suggesting, ensure your battery voltage is correct. If not, try shutting down all batteries, charge, and reconnect all to do a "clean reboot". Hopefully all that ails goes away. If the Check Engine light is still on, it's possible if the issue is gone that it will auto reset after a few drives. Best would be to invest in a scan tool compatible with your powertrain and pull the codes for much more specific info. Post your codes on the forum.

Standard license plate bolt set uses a nylon insert into a big hole in the fiberglass. Then, when the screw is inserted, the diameter of the screw locks the nylon into the fiberglass. Good as it's one sided on / off. Good as it's not metal that rusts. Good that the fiberglass can be drilled out to insert since the old built in nuts look rusted. Any auto parts store.

It is very common that headbolts are replaced and not reused. Do check if sealant, oil or dry is how the bolts go back in.

One of the cleaner motor bay pics. Much nicer to work on stuff. Did you straightedge measure the block deck and head? All straight?

This is the muffler I put on my ISM500 https://www.amazon.com/Aero-Exhaust-Performance-Muffler-AT5050XL/dp/B07HZ3NVBX I would also post an audio clip, but it sounds very much like Bliksem's...maybe a very small touch less muffled. Where it sound neat (and the only time I hear it in the driver's seat) is going up Vail Pass thru the tunnel and floor it 🙂 It is straightforward plumbing job. Just measure your sizes, get pipe / adapter / clamps to match, get some quality hangers, ensure you are connecting to something solid, put some rubber isolators in the strap and go for a drive.

No magic in that connector. If you can find the right one, awesome. If it takes more than 10 minutes, just clip it and put some solderless bullet connectors on them right size for the wire gauge. Just take a picture to get the right wire to the right wire. I would put some antixodent on them, and tape them up to make them water tight and move onto the next mission.

Weigh your rig front / back / tag and set YOUR pressure to your tire specifications. Doesn't make any difference what others are doing.

https://www.homedepot.com/p/Gardner-Bender-12-10-AWG-Snap-Connector-5-Female-5-Male-Yellow-10-Pack-15-162P/205861878 Keep it simple. Crimp, connect, wrap with some electrical tape.

I second just go to HomeDepot and get a higher amperage connector and get er done. There isn't any good reason to care that it's OEM if the connector you use meets the electrical requirements (voltage / polarity / amperage)

Good to hear of a success story. We should have a place to organize Service Providers, their specialty, reviews and contact information.... This is all good info, but if you are broken down on a road in some state...currently difficult to find the information outside of a Google Search. if no other site creates this, I might when I find some spare time...

I would monitor engine temp as that's what is important. Fan speed is not. Since you removed the electronic guts that monitor speed, and replaced it with mechanical, then there isn't a current way to monitor. You could hack stuff together and take a few days, but why? Inline with what? The hydraulic pressure? If you have a wiring / plumbing diagram for what you currently have, then post it for more ideas specific to your question. but since it's been modded...modded to what?

https://www.delcity.net/store/Kwikee-Electric-Step-Motor/p_810376.h_799468