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Topic Boards => Dodge - Chrysler Chassis => Topic started by: Mlw on September 30, 2021, 02:30 PM

Title: Dodge MB400 360-3 wiring problems
Post by: Mlw on September 30, 2021, 02:30 PM
HI Guys,

After I introduces myself in we now will dig in the mess created by the former owners hobbying skills in electronics  N:(

I myself are not a real electrician also, but understanding it. For me there is one golden rule. Don't go diggin in the original wiring Harness, but add and color code.

I wished somebody told the former owner of my Dodge Minnie Winnie that, because the amount of Car Wire Cable Clips and plastic insulate brass connectors and therefore corroded wires i have found after i opened up the dash and the hood are unbelievable. The radio was connected with such a lenght of orange wires (one color to be used for all connections) i could take the radio out of the dash and lay it on the salontable which is positioned behind the drivers seat, as long as I disconnected the antenna.

After getting all the orange out I looked deeper in to the wiring and felt more like crying by the minute. Red and black wires were clipped together disapearing in the dash or in wired cable harnesses. When i later tried to start the engine it wouldn't start and just gave 1 turn. Measuring with my multimeter I had 11.52 volts at the battery and 8.52 at the car electronics even after playing with the connectors at the batterypoles.

I connected a batterycharger with starter capacity. Charging 25 amps, 13,42 at the poles but 1 volt less at the car electronics. I could start the engine however.

So i started by sanding all connector, and it did improve. For testing purposes I had the ignition on (without the motor running)  and noticed that my ignition coil gets boiling hot when I do that. Is this normal? (Ignition coil is fine when motor is running)

It doens't stop there because the alternator isn't charging. (I found this out when buying the car) the strangest thing however is the fact that I saw my balast resistor wasn't connected (normally it shouldn't be possible to start the car?)  but after I did connect the breaker circuit there was some charging capacity but not enough.

Headlights and High beam don't work anymore, and as far as I remember they did when I tested them buying the car.

And last but not least, my Oil pressure gauge isn't working. I have a three way sending unit (red, black and white)  and the white one isn't connected. I still have to find the right wire for the gauge. I've found severeal wire diagrams on internet but none tells me the right wire for the oil gauge.

So... HELP!  ;) :D
Title: Re: Dodge MB400 360-3 wiring problems
Post by: Mlw on October 08, 2021, 12:03 PM
Wow it seems I'm really the only one having this problem.  Hm?

I've found a big help here on the forum, the 1978 - 1982 Dodge Motorhome Chassis service manual. If you are planning doing the maintenance at your motorhome yourself. Buy it. It is tremendous source of information of 490 pages.

There is also a wiring diagram in there but unfortunately the colorcoding don't seem to match. The diagram itself however does so it's still a big help and started to dug in to the mess myself.

As i found out, you don't seem to need to cut into your wiring. just try to find the multiple connection points to be found under the dash (see pics 1036 & 1039) they are connected directly to your fusebox. 1 for your dashlights (with dimming from your headlight switch), connected to fuse 1. One to the ignitionswitch connected to fuse 2 (cutting of power when you shut off the ignition) and one  ground. If there's more i will re-edit the post. Be smart and mark them with function and fusenumber for future reference.

So all the cutting in the wiring by the former owner was completely unnecessary. (except for the radio perhaps) A lesson to take here is, inform yourself of the functionalities of your vehicle. It will save you a lot of headaches afterwards.

Finding these connectionpoints I decided to rip all of the former's owner handywork out (calling him an  $@!#@! multiple time with every wire  :angel:) and reconnect his add-ons i want to keep. To my big suprise the domelight started to function the right way.  ??? ??? ???

the way it worked was: remove the lamp from the socket when you don't want light, (and burn your fingers when the light gets to hot  $@!#@!) replace the lamp when you do want light. :D

Now it functions again like it should. When the driver or passengerside door opens or when you turn the headswitch the light goes on.  :)clap :)clap :)clap

What were the add ons I've found.

- dashlight for the Hazardlights (because both turn-signall lights flashing at once isn't clear enough)  D:oH!
- dashlight that flashes one time only when you turn left or right, My suspicions are that the light actually checks the turnsignals on your trailer. I had one on my Opel Kadett many, many years ago. As I don't have a trailer i can't test.
- '90's aftermarket radio/cd player
- wiper interval
- speedcontrol
- rocker switch for the highbeam.

The lights i will need to keep, because two holes in your dash isn't an option.
The radio will be replaced and connected decently to the auxiliary battery.
The Wiper interval and Speed control I will keep of course.

The Wiper interval didn't seem to work correctly, and here is the reason why you NEVER use Car wire cable clips. They cut into the insulation of your wiring hence expose your wiring to the elements. As the contact between clip and wiring is minimum you will get malfunctions as soon everything starts to corode. Although they seem very handy and tidy, DONT USE THEM if you don't want future problems.

And as last, if you add items to your car and connect them directly to your battery, it really is advisable to put a fusible link between the battery and the item you are connecting so the next owner doesn't find the:

Headlight directly connected to the battery, without fusible link. Colorcoded with a wire which normally stands for ground in Europe.(see picture 1026)

Wiper interval directly connected to the battery, without fusible link but the right colorcode. (see picture 1026)

That the former owner didn't burn this motorhome to the ground really is one of gods true miracles.  :D :D :D

two questions at the end.

The air shaft (picture 3) runs down to the firewall so water runs freely over all the electricity attached to the firewall  because there is a gap between the hood and the Aishaft so it fits snugly in its surroundings. IS there anybody out there who did something about this?

Does anybody has the right fusebox index for a 1979 dodge M400 chassis. I've found one of a 1983 Ram Van and altough it seems pretty accurate I seem to miss some items on this list or there are items on there that aren't there in my motorhome.

Title: Re: Dodge MB400 360-3 wiring problems
Post by: Oz on October 09, 2021, 07:31 PM
Quite a job there.  I fear electical problems almost as much as an angry wife. 
And true, having a shop manual is the most important tool to have.
Title: Re: Dodge MB400 360-3 wiring problems
Post by: Mlw on October 12, 2021, 07:11 PM
 :)clap :)clap :)clap

Yes, both are not wishable  :D

Luckily I don't have a angry wife (yet)  W% Wiring problems more and more.

I pretty much found out there is almost nothing the former owner didn't get his hand on and me asking constantly, why the hell would you do that (in the way you did).

Now autumn has arrived it's raining cats and dogs here in the Netherlands and altough the motorhome has a hood, i found out sitting in the motorhome with the doghouse off it raining as hard inside the motor compartment as out and therefore a lot of connectors are corroded, but how you could think that you can solve your problems by adding cable clips is beyond me. Should there be a seal between the hood and the chassis? I doubt there ever was one because there is no glue residue.

I guess i will end up replacing the wiring harness which will be not be easy as I found out my motorhome is the California edition with all the extra (emission) sensors. If you look at the Motorhome manual and the wiring diagram, there should be an extra panel to read out all the sensors, but it's not there. It's getting more confusing by the minute, because when you can't read them out why add all the sensors and wiring?

As I tried to fix my oil pressure gauge (still didn't succeed) I found the speed switch emission (see picture). The sealant of the circuitboard is damages due to dirt and moisture. Could this be the reason my oilpressure gauge isn't working as the cables from the oilpressure switch seem to be connected to it. I'm totally confused why. There is no information to be found about it so what does it do?

As I hope everybody understands I'm loosing a tremendous amount of time figuring out not only the former owners handywork but Chrysler as well, so still hoping there is somebody on the forum here that can help me.
Title: Re: Dodge MB400 360-3 wiring problems
Post by: Oz on October 13, 2021, 08:02 PM
No seal between the hood and engine compartment.
Title: Re: Dodge MB400 360-3 wiring problems
Post by: Mlw on October 17, 2021, 12:30 PM
I allready thought so.

I have to figure this out because this won't do.  N:(
The waterleakage caused more problems, I will add a picture tomorrow.

I actually made great progress last week. I've finally found the problem with my oil pressuremeter. I've found the right wire underneath the wiring and 1mm thick layer of gunk that's covering the whole engine. It was at least a good sealant to all the water entering the engine compartment.  :)

the problem however was the oilmeter maxed out as soon as it was connected. As to expect the former owner solved this by yanking the wire. Why would you need a oil pressure gauge?

 Investigation showed my oil level sensor is dead and it seems I'm not the only one with the problem. I put it on notify at Rock Auto, received an email it was in again with limited stock, but within the hour it was allready gone leaving me empty handed. :(

Furthermore I brought the car lighting back to original, yanking all the cable wire clips and  short circuits the former owner created which melted one of the connections of my dimmer switch. and that makes the 3rd reason I believe it's one of gods miracles the idiot didn't burn the motorhome down as the connection was covered with thick layers of carpet. As all "good" things comes in three, let's hope this is the end of this then. The only thing i have to reattach are the park and marker lights, but as it actually not allowed to run them here in the Netherlands (because good visibility shouldn't be of course)  I'm going to put them on a separate switch and run them from the coach battery.

Title: Re: Dodge MB400 360-3 wiring problems
Post by: Mlw on October 18, 2021, 04:48 PM
Today I did something different because i have to wait for a soldering station coming in. I'm going to erase all horrors the former owner did to the poor thing and make it healthy again.

For that I need to erase all cable wire clips. cut the wire and erase corrosion. then solder the wires back together again and seal them with heatshrink.

The connectors are all corroded so I'm going to replace all of them with watertight ones.

So most of the things are solved or will be solved. But there is still one question left that stays unanswered

What does the Speed Switch Emission actually do. At the moment it's connected to the Oil level sensor and chances are that this is just more idiocy from the former owner because on the wiring diagram it's not at all connected to the oil level sensor, but to the electronic ignition control unit, the ballast resistor and than to the trip computer and a vacuum solenoid, which would make total sense instead of being connected to a oil level sensor.

Because it's now connected to the oillevel sensor is probably the reason of the problems with my oil pressure gauge, the state of the sealant of the Speed emission switch and the fact the oil level sensor is blown.