When I bought my 88 E350 last year, the previous owner had hacked some stuff pretty badly. To start it, there was a dash switch, and if you wanted the blower to work you had to connect a wire under the hood. I've been just living with these issues, but finally got sick enough of them to fix it.
First was the starting. I thought it had a bad ignition actuator since it had play in the key tumbler. I got the part ($12 at Napa), tore it all down and after pulling the old one it looked fine. I installed the new one anyways, then as I was setting the switch I found there was an aftermarket addition- A relay and microswitch in the start circuit, which the guy had to know about since he drove it for a while, but seemed to forget about when I bought it. So, I bypassed the relay and it starts fine with the key now. One problem down.
Today I had some more time so I went after the blower. The controller only handles the ground to the blower- The power comes from a relay that is controlled from the panel. A little digging and I found everything in the dash was just fine. I pulled the right side battery, and tried to unplug the relay (rectangular box next to the voltage regulator). Well, one of the pins came out with the plug so there's the problem. The real problem though is that this part is hard to get a hold of now. So, I reworked it to use a regular four pin relay by clipping the plug off and putting female spade connectors on the three wires. I made up a fourth wire with a female spade and a ring on the other end, the mounting screw goes through the ring and grounds the activation circuit through pin 85. The small wire connects to pin 84, the other side of the coil circuit on the relay, and the two larger wires go on pins 30 and 87, the input and switched output of the relay.
The only issue left is the fuel tank switch, I only have the front tank. I haven't really played with this yet, but if someone has a wiring diagram for this I'd really appreciate it.

 

Sometimes hack repairs just need to be completely undone and the original system or configuration restored/rebuilt to its original state.

For electrical issues I'd either secure a factory EVTM or wiring diagrams manual, typically found on eBay for decent pricing. Not sure if your year would be considered simply "old" or "vintage" but that would affect the cost.

Autozone has free schematics to download----registration is necessary but they don't SPAM you to death. That's worth looking into.

Hope your repairs go easier than trying to figure out why someone would do such things.

 

Unfortunately AZ seems to think these have no wiring beyond the lights, so no diagrams for the blower or selector switch.

Sent from my Brigadier using IB AutoGroup

 

Hmmm---that's interesting but only if we define "interesting" as maximum frustration.

Franklin in the Electrical & Wirings forums would be my go to guy for schematics in a hurry then.


HTH

 

I found a fuel selector diagram here for my '88 E150
1985 F150 Fuel Problem. Please help!! | FordForumsOnline.com

The wire colors may vary but the circuitry is mostly common. I replaced Ford's selector system with a different version here:
https://picasaweb.google.com/jimandn...50FuelSelector

They show the colors on my '88.

Good luck, I hate car wiring work.
jim

 

Well said.,...jack

 

I finally got a chance to play around with this issue a bit, and the diesel vans are quite different than the gas ones. The gas ones of the era switch power to fuel pumps and have a purely mechanical valve that is moved by the fuel pressure. The diesel ones have an electrically switched valve. It is operated by swapping power and ground on pins 1&2, with the front tank being pin 2 powered and pin one grounded. It turns out I most likely have a bad switch, as the power and ground for pin 1 never show up, but there is a solid power and ground to the switch. This information is kinda hard to come by online, so hopefully if someone is dealing with this issue in the future they'll see this and have a little less wasted time.

 

Over 8500#





Under 8500#

 

I bought a 91 E350 about 5 years ago. The guy that owned it was a marine mechanic and he said his specialty was electrical. After seeing what he did to that van, I feel sorry for every boat owner who's boat he worked on. This is how the alarm was installed. Some of the wires were several small wires pieced together with butt connectors.

 

Needs a little duck tape, maybe? haha