99 Ranger No Speedo, internal lights, wipers, or windows.

[99DangerRanger]

Help needed.

I am in need of some advice, my 1999 Ranger 4.0l RWD Manual has been having year long intermittent electrical issues. Electrical is far from my realm of expertise. Frequently my truck will start with no cab lights, speedo, wipers, or electric windows and after a while it may or may not come back on. (All other gauges work, just speedo fails) While running with power loss the truck idles like trash, misfires on downshifts and doesn't regulate fuel mix. I can hear what I believe is the ecm relay turn on and off under the glove box. I can't seem to solve the problem.

What I've changed, swapped, inspected:
- Rear diff VSS (receives voltage fine)
- Engine to firewall grounding strap (continuity is good)
- Fuses (some seem old and possibly incorrect amps, might replace all)
- Wiper and window relays
- Battery & terminals
- Battery negative to ground.
- New ecm relay.
- I've inspected the GEM, seems to be getting power and works as soon as ECM clicks.

It's a little cold tonight but I'll run a multimeter on the ecm tomorrow and verify if it's recieving voltage but I doubt it. Anyone have an idea of where the loss is happening and why it's intermittent? It's gotten bad enough recently that it hasn't worked in days with a brand new relay.

 

[99DangerRanger]

Also I have to drive from Toronto to Calgary in a month for work. Please help lol.

 

[Shran]

What you are describing sounds like the battery saver relay, not the ECM relay... the battery saver circuit is on a timer that counts down when you turn the ignition off and before you open the door. This is a pretty common issue on other (newer) Ford vehicles and is more complex on those because it's built into the instrument cluster. For example when it died in my F250, the gauges, power windows and radio would not work.

I would be checking for corroded grounds throughout the cab and the wiring to your GEM module, make sure your door switches are in good shape too.

 

[99DangerRanger]

What you are describing sounds like the battery saver relay, not the ECM relay... the battery saver circuit is on a timer that counts down when you turn the ignition off and before you open the door. This is a pretty common issue on other (newer) Ford vehicles and is more complex on those because it's built into the instrument cluster. For example when it died in my F250, the gauges, power windows and radio would not work.

I would be checking for corroded grounds throughout the cab and the wiring to your GEM module, make sure your door switches are in good shape too.

Awesome, thanks so much! I'll take a look and let you know how it goes!