Help: 1996 blower motor wiring, relays

[Anak]

I thought I would follow the addition of relays as outlined here:

http://www.jeepforum.com/forum/f11/...blown-melted-resistor-switch-wire-fix-580627/

However, it seems there is a bit of hitch in that if you have a 1996. I am guessing this is a '96 only issue since '96 is somewhat of an illegitimate child between '95 and '97. I suspect the challenge revolves around the lack of the second green wire. On mine there is only one green wire going to the resistor plug. That simplified the question of which one do you cut, but it did not get me where I need to go. I now have a blower motor, but only on high. No low or intermediate speeds.

Does anyone have any idea how the 1996 wiring diagram differs from this diagram:

My efforts to find a '96 version have been in vain.

Build date in 04/96 for what it may be worth.

I have found that if I jump from one wire to another I can get different speeds, but not through the blower speed selector switch.

Selector switch, resistor and blower motor are all new.

I don't think any of my parts are at fault. I get clicking relays as I switch from one speed to another, but power is not getting through the lower speeds to the motor. Somehow I need to recreate the circuit to the motor when at lower speeds, but I am either lacking the right information or out of my league. Or both.

 

[souske]

Do you get voltage out of each position on the output of the switch?

 

[Anak]

I did not test for that, but the fact that I can hear relays trip with each move from one position to the next tells me that the relays are being driven by the switch.

I have managed to make it work, but I am not convinced it is a solution.

I took the green wire out of the relay scenario and reconnected it directly to the resistor. Running that way I get all four speeds out of the system.

I have a strong suspicion this largely negates the purpose of the relays though. I think I am now back to running full current through the switch/connector that is the root of the problem. I think all I have done now is add a layer of complication (relays) to the system with no real benefit (reduced load on switch/connector).

I am wondering if the addition of a diode would solve this problem. I mention this because I found that if I jumped the relay for the green wire I would then get the low speed on the fan while the switch was in the low position, but as soon as I switched up one speed the fan immediately went to high speed and could not be turned down or otherwise controlled by the switch. Disconnect the jumper and things are back to nothing. Something is connecting, but then not disconnecting in that scenario (the relay?)

There is probably a simply solution, but I don't know enough to find it.

 

[souske]

Yeah, I didn't read the link until after I posted that.

Can you draw up a circuit diagram of how you wired everything up? Then either post it or bring it to the meet and greet Monday

 

[Anak]

Maybe. Drawing up a circuit is not my forte.

All it that I have really done is add a relay in the middle of the wires that run down to the resistor under the dash. Pulled fused power from the battery. It is just another switch, but ideally one that skips pulling the real current through the blower motor switch up on the dash.

I can run three of the four through relays, but the green wire I cannot.

There is something else going on here that I am not grasping, and it is probably unique to 1996.

 

[souske]

High should just be straight power, no resistor
Does the high circuit relay switch? Or only with the jumper?

I have a 96 if looking at another one would help.

 

[techno1154]

Actually, there are no relays in the blower motor circuit. If your XJ have relays in that circuit then the previous owner added them.

If you pull the resistor pack out of the blower air box you will find a thermal fuse there. Check that fuse for continuity. When my XJ messed up, it was because that fuse was bad.

By-the-way, there is some inconsistency between the wiring diagram and the green wire but I do not remember exactly what it was. Mine work fine now at all speeds. Now to get the AC compressor to run,.....it only run when the mode switch is set to defrost.

 

[Anak]

High should just be straight power, no resistor
Does the high circuit relay switch? Or only with the jumper?

I have a 96 if looking at another one would help.

The high circuit is switching, and via the relay.

It is the low circuit where I am not able to use the relay.

The wiring on mine seems to be the opposite of the schematic I posted. The yellow/tan is my high speed. Green is my low setting. I don't know if that is another '96 feature or if it is compliments of the handiwork of previous owners.

What I really want to know is what the change from two green wires to one green wire involves in the wiring harness. I don't want to disassemble an entire wiring harness in order to figure it out.

 

[Anak]

Actually, there are no relays in the blower motor circuit. If your XJ have relays in that circuit then the previous owner added them.

If you pull the resistor pack out of the blower air box you will find a thermal fuse there. Check that fuse for continuity. When my XJ messed up, it was because that fuse was bad.

By-the-way, there is some inconsistency between the wiring diagram and the green wire but I do not remember exactly what it was. Mine work fine now at all speeds. Now to get the AC compressor to run,.....it only run when the mode switch is set to defrost.

I am the one adding the relays. I am trying to duplicate what I linked in the first post.

I have everything working right now, but I am not convinced it is the right solution. I am trying to take all the real load off the switch in the dash because I don't believe it is up to the job.

 

[ehall]

Do you have the FSM? There are loads of circuit diagrams in there, each one shows wire gauge and color, makes it easy to find what does what

 

[Anak]

No I don't.

I wonder if the '96 FSM covers all the variations, or if I will also need a '95 and '97 to properly cover my bases.

 

[ehall]

IIRC 97 was the year of the bastard wiring

 

[techno1154]

I am the one adding the relays. I am trying to duplicate what I linked in the first post.

I have everything working right now, but I am not convinced it is the right solution. I am trying to take all the real load off the switch in the dash because I don't believe it is up to the job.

OK. I see what you are doing. I do have a CD based manual for the 1996 year model. I could/would send you the pages you need but I do not know how to attach PDF files on this forum.

 

[Anak]

If you could just look at the schematic for the blower motor and tell me what course the green wire takes from the resistor to the blower motor that might be all I need to know.

Sleeping on it, my guess is that the bean counters decided they could save a bit of copper by splicing in closer to the motor. I doubt the FSM will tell me anything about where to find that splice, but just the confirmation of its presence would be a big help.

And if there isn't a splice, then what is there that goes between the blower motor and the resistor?

That information would either set me on the right course or provide more fodder to noodle over.

 

[techno1154]

If you could just look at the schematic for the blower motor and tell me what course the green wire takes from the resistor to the blower motor that might be all I need to know.

Sleeping on it, my guess is that the bean counters decided they could save a bit of copper by splicing in closer to the motor. I doubt the FSM will tell me anything about where to find that splice, but just the confirmation of its presence would be a big help.

And if there isn't a splice, then what is there that goes between the blower motor and the resistor?

That information would either set me on the right course or provide more fodder to noodle over.

OK. have been gone for awhile.

The schematics are unclear as to exactly where the wires exit to the engine compartment but if I remember clearly, they exit through the large connector/fuse panel on the driver side.
There are only 2 connectors shown for that circuit, C1 which have a 12AWG dark green wire. Connector C108 is at the blower motor itself and connector C214 is at the resistor block.
My XJ build date is 06/96. The schematic you posted is the same one in my manual page 8W-42-4.
Sorry I could not be more helpful.

 

[Anak]

That is indeed still helpful. If nothing else it tells me the '96 FSM is not going to have the information I need. I don't need to pursue that rabbit trail.

I have seen another '96 with the single green wire in the JY. I simply need to find one when I have the time to disassemble the wiring harness and figure out how they wired this thing.

 

[techno1154]

The drawing you posted show 2 connectors,.....

C110 located at the left rear corner of the engine compartment
C242 located center bottom of the kick panel.

Those are very different to those on my XJ.

 

[Anak]

I think C110 is the plug for the blower motor and C242 is the plug for the resistor. I have those on my '96, but C242 is slightly different in that I only have the one green wire rather than the two shown.

It is that green wire at the bottom of C242 that has me messed up. That diagram shows two wires there, and that is indeed the arrangement I have seen in most XJs in the JY. On mine however, there is only 1 green wire. So the question is, where is the other wire?

 

[techno1154]

I think C110 is the plug for the blower motor and C242 is the plug for the resistor. I have those on my '96, but C242 is slightly different in that I only have the one green wire rather than the two shown.

Coming off the high speed terminal of the blower motor switch should be two wires on go to the resistor pack and the other directly to the blower fan. On some XJ's that wire doubles at the switch itself. Others seem to have a splice inside the harness itself.

The low speed settings get power directly from the heater control switch through the entire series (I think 3) of resistors.
M1 go through 2 resistors and M2 through 1 resistor.
On high speed the resistors are bypassed but the wire parallels or "T"s into the wire that come off the resistor pack to the fan.

Hope this helps.

 

[Anak]

Coming off the high speed terminal of the blower motor switch should be two wires on go to the resistor pack and the other directly to the blower fan. On some XJ's that wire doubles at the switch itself. Others seem to have a splice inside the harness itself.

That possibility of a splice inside the harness is what I am suspecting to be the case here.

I don't have two green wires coming off the blower motor switch, nor do I have what the diagram shows with two green wires coming off the bottom of C242 (as drawn). At each of the relevant connectors I only have one green wire. The second green wire is missing. At least to the eye.

The next questions becomes where in the harness are they likely to have buried the splice and what do I have to disassemble in order to find it? This is where I am thinking I may be best served waiting until I find the proper candidate in a junkyard and can do some exploring without having to worry about collateral damage.