1998 33WB Chieftan [Ford] will not start

[Andrew276]

Hi everyone,
I changed out a coach battery and saw a spark. Now the engine will not start. When I turn the key to ON position the dash lights up and instruments activate. I can operate the slide from the ON position. Everything works from ON position as far as I can tell
When I turn the key to crank I hear a single click from dash but the starter does not engage.
I have checked the fuses under the dash and in the engine compartment and all look okay. I do not know how to check modules or if they can be checked.
I have attempted to start with Aux Battery and Aux Start to no avail.
The generator will start and operate.
The battery is good and terminals are clean.
Any help would be appreciated.
Thanks

[Andrew276]

Thanks for looking at this. My dad came over and we tracked the issue to the fuse terminals being corroded. We used a fingernail file on the fuse terminals, shined them up, put them back in, and voila she started.

[Eagle5]

Hi Andrew,
Sounds like you have a good Dad there! Glad that you all have it fixed now.
Welcome to the forum.
Eagle5

[Bobn1957]

You were lucky, that spark could have easily fried the engine control unit (ECU).

[Andrew276]

Yep, my wife calls me Lucky Dog all the time.
Happy RVing everyone.

[Morich]

If I understand what you are saying and the RV engine was off, Key off also, The change and spark at the coach battery had nothing to do with the engine failing to crank as they are fully separated at that time!
The reason for the spark is that not all the Rv items are disconnected and when putting the cables back on the coach battteries, those items start to draw power. Nothing involving the chassis 12VDC!
Your chassis drawing here:
https://www.winnebago.com/Files/File...998/126577.pdf
Click to get a better view of this snip!


I've drawn out how the two 12VDC groups get connected at different times. This is a very common thing to have trouble over the years and something we often deal with here on the forum as it is such a vital part.
The blue line is how the chassis/ start battery gets to your starter and that is what failed you this time. It is one that does have lots of connections to get dirty, so being aware that is one of the most common start problems may help a lot in the future!
This MODE SOLENOID also is a frequent problem with age and it has two times that we may need it.
One is when we have a weak start battery and need a jump start! There is a switch labeled AUX/boost, etc near the driver. When we push that switch, it sends power down a wire LR to the solenoid and makes the contacts of the solenoid close. You can often hear it thump! Big contacts that connect the two cables from start and coach batteries together. That is like a jump start without cables! Blue line gets connected to green line in solenoid!

But that wire LR also is connected to a point which has power when the ignition is on and operates the solenoid every time we turn the key on as a way to let the alternator recharge the coach batteries a bit as we drive.
Reason for this being a frequent problem is that the contacts arc a bit every time we start the engine! They wear out quicker than we like and when they do, the coach batteries stop getting charged as we drive!
Point to know but nothing to worry about is it is working and they can last decades! Your RV may have a new one already??

Big thing to know is that there are two different 12VDC systems and they get connected at these times. When you have trouble, the first thought is which system, the normal truck/ car parts or the RV coach parts and then look at the one that has trouble!

Good luck and enjoy!