syncview

Hello everyone.

This is regarding a 1996 RHD cherokee on which I'm working on - problem is: whenever I honk horn, the engine stumbles as if something is cut off the electric supply.

Now, I tried some quick tests and removed the ground of both horns and tried pressing the button on steering wheel - nothing happens.
If either horn is connected back, engine stumbles.

now I didn't try pressing the horn button for too long to see what eventually happens, because I'm thinking its either shorting out to the 5v power somehow OR the ASD 12v or the horn circuit + is being shorted to sensor ground.


Posting here to get ideas and suggestions from people who are literally seasoned with cherokee's electricals


thanks in advance!

toasterknight

Sounds like a bad clock spring to me. If its going out it can cause some funky issues.

Lowrange2

I agree. Replace the clock spring and report back.

I've seen this same thing in Ford trucks.

syncview

nope, not the clockspring - tested it all ways and its good to go

plus i removed the clockspring and activated the horn by grounding directly, same thing!

I've run out of ideas, horn wiring is good - no fuse blown

The only thing I can think of now is to somehow monitor ASD+ / ECU 12v Feeds and see if voltage drops

I saw the wiring diagram and #A7 wire goes from PDC to junction block which powers the cigar lighter / horn - I'm assuming this wire is weak

CCKen

I don't have a '96 FSM (wiring diagrams) but I think the horn system is the same for the '95 and '97 (which I have).


By the looks of it, the horn relay control coil is powered from the battery at all times. The horn switch in the steering wheel provides a ground to the relay control coil, which, when activated, pulls in the relay power contacts to route battery voltage to the horns, which are grounded through the chassis structure.


If you remove the horns from the chassis structure and the engine does not tumble/quit, there' a possibility there's a bad ground circuit in your engine bay. When the horns are connected to the chassis power from the horn grounds is finding its way to the ground circuit(s) of other circuits.


I think you should address all the grounds in the engine bay - chassis and engine.


I think the '96 has the PCM ground at the oil dipstick tube mount bracket. I would start here. Remove the wire ring terminals and clean them with sandpaper and do the same at the engine ground point. Reassemble and try 'beeping' the horn again to see what happens. If the same, move on to all the rest of the grounds in the engine bay and repeat the ground cleaning process.

syncview

Indeed, I also don't have the '96 FSM - and its pretty different, the PDC and Junction block, seems like 96 is EPECIALLEEE.

I'm following the 97 wiring and so far so good, wire colors are different but not a problem.

And, that is a great idea - first I will ground the horns directly from batt-, then see what happens. I checked all the ground connections using the voltage drop method, the max drop I got was like 5mV. Both engine off and running.
But I will redo the grounds anyways.

Will report back tomorrow

CCKen

Grounds integrity is checked using an Ohmmeter.


Thistest should be performed with the battery positive cable removed from thebattery.


Disconnectboth battery cables, the negative cable first. Reconnect the battery negativecable and perform the test as follows:


(1)Connect one ohmmeter test lead to the vehicle fender. Connect the other testlead to the battery negative post.


(2)The resistance should be less than one ohm.


(3)If the resistance is more than one ohm, check The grounds for being corroded orloose.