First time poster here. Kinda struggling with this one since any useful information is incredibly scarce.

I've got a 1985 Cherokee Chief, 2.5 I4, 5 speed. Only recently got it running after doing a nutter bypass and I've found that the alternator is not putting out any power. I checked both terminals on the wire that connects to the top of the alternator and the red wire does have the expected ~12V but the thinner tan wire has no power at all.

I traced the wire all the way back to the 5 pin harness and it looks fine outwardly. I'm really at a loss with this and it doesn't help that information on wiring for this year and especially with these options is scarce at best and usually conflicting.

Any suggestions?

 

Doesn't that connect into the ignition?

 

Whats a "nutter bypass"?

 

On older Cherokees it's very common to bypass the ECM and go straight from the ignition module to the distributor. It's simpler, faster, and sometimes cheaper than trying to fix the system that came in these things.

I believe so. It's normally supposed to get about 12V when the key is turned to "run" but mine doesn't get anything. As far as I can tell my ignition switch is fine. Everything else under the hood that should get 12V in run is getting it.

 

Have you pulled the ignition cylinder and cleaned up the contacts? It's not a lot of current, and low voltage == very susceptible to dirty contacts.

 

Good point. I'll have to try that. Honestly after my last ignition switch job on my Camaro I've been treating it as a last resort but at this point I guess it's better to cover all my bases. Supposing it isn't that, any other ideas?

 

Broken wire from the ignition?

 

I read about it needing power from the instrument cluster and sure enough there is a brown/green wire same as the one on the alternator that goes to the instrument cluster. I provided power to the contact on the harness using a power probe and the alternator started putting out. I tried this twice and on other contacts to make sure it wasn't a fluke and sure enough this wire does go to alternator. But it doesn't seem like the contact on the harness lines up with the contacts on the cluster.

 

That could be true. Was just watching Hater's Garage on YT and he discovered the same type of situation on a ****box Charger 2.2

 

Well... I got it working...

After loosely following the wire it seems that it goes to the ECM which then sends a signal to the instrument cluster harness which explains the lack of a contact on the cluster itself. I imagine that was probably for a different trim or maybe the Wagoneer.

Anyway, my ECM was fried from the day I got it hence the nutter bypass so I'm assuming a new ECM would fix the issue but I'm not about to go out and buy a new ECM just for a single wire to work so I opted to jump power from orange wire on the diagnostic harness (computer is bypassed so that part of the harness is dead weight anyway) to the exciter wire and that solved my problem.

Not clean, I actually really don't like that I'm doing it this way but at some point I'm just gonna do a standalone harness anyway so whatever works for now...