'88Xj: #1) No HVAC Fan, #2) Body Connector Leaking H2O

[RAVC1]

Issue #1
I have had difficulty getting my HVAC fan to work in the recent months but, this has degraded further this week and I am not observing airflow from dash vents or defrost (note A/C does not work - AC clutch stooped working ~2 years ago???). I think I have low airflow sometimes but, nothing above this. All other aspects of my HVAC have been fine except fan speed and a lack of AC.

I strongly suspect the resistor block...

http://naxja.org/forum/showthread.php?t=1126213&highlight=HVAC+fan

Can anyone give me a better idea regarding its location and appearance so, I know what I am looking at? "Right side of heater/AC housing" is not helping me...but, I am at my pc now.

However, this Xj has a tell-tale I regard as unique. I have experienced problems with the fan operation before so, I exchanged the HVAC control panel with one of my spares. This helped yet, the fan would still stop working but, less frequently. Cycling the fan switch usually restored fan operation. The unique aspect I am referring to is the brown connector housing that connects to the rear of the switch has clear signs of (...a small degree of...) melting. Why? Unfortunately, I cannot recall which of the (5) terminals the melting is near. I cannot recall if wire insulation was impacted either. I will be removing the dash this weekend to resolve this because, I must have airflow to the windshield with all the rain we have had here in MI. October is likely to bring more of the same weather conditions.


Issue #2
I began noticing rain water at my feet this spring and identified the body connector behind the fuse block as the source of the leak. I taped a couple of shrouds above it in the engine compartment and this has helped but, the leak remains. Is it know how this connector leaks after it is separated from the fuse block? I separated this connection several years ago and this makes me wonder if I have inadvertently created this leak. In other words, if I separate the connector again to place some sealant where am I likely to need to apply it to remove the leak? I think there is actually a gasket surrounding the connector that also passes through the center of the connector (i.e., horizontally or vertically but, not both) and the central screw passes through a hole in this portion of the gasket. I vaguely recall calling the dealer regarding this and they were stumped... Suggestions?


Help is appreciated... is known for this!

 

[Green Mesa XJ]

Not sure how you should proceed. Maybe spray a sealant on the out side if it's all tight.


Sent from my iPhone using Tapatalk

 

[JeepNoob]

Thermal events with the blower switch seem to be normal with our rigs. I seem to recall that some guys think it has something to do with there not being a relay in the blower motor circuit. Blower motor gets worn, old, whatever, bearings start binding, blower motor tries to draw more amperage, bam, blower switch and the connector melts.

The resistor block, at least on mine, is on the passenger side, on the underside of the air box assembly, next to the vacuum thingy for the mode doors. If you were to lay on your back in the passenger foot well, it's pretty much right in front of you. Mine had a black plastic cover, but I lost it. The connector for the resistor block looks a lot like the blower switch connector too. It's bolted in with two little, I think, sheet metal screws. Remove those, pull it out.

 

[RAVC1]

After some preliminary testing/examinations:

1 - What is the correct resistance (ohms) for the fan blower motor? The motor in my 1988 Xj measures 12.45 Ohms. I have two parts cars and the fan motors in these measure ~21 Ohms and ~24 Ohms. This information causes me to suspect the fan motor in my 1988 Xj is okay but, this has yet to be demonstrated...

2 - My resistor block looks fine from a physical perspective. All coils are intact and so is the resistor. However, the resistance values I measured do not match those in my manual. I suspect the resistance values are incorrect because the part is old and some corrosion is visible.

3 - I checked the voltage at the supply connector to the fan. I see ~14.5 VDC only when the fan speed selector switch is placed at high. Regardless, the fan never moves air. All other fan selector switch positions result in millivolt (mV) level voltage readings. These low and two intermediate fan speed supply voltages seem inappropriately low.

4 - The vacuum transducer/actuator next to the resistor block appears to be functioning correctly. In turn, I do not expect a closed HVAC system door to be an issue in this.


With all of this is mind my primary concern is the fan supply voltage measurements I observed. Additionally, if my fan motor is not rotating with ~14.5 VDC applied this indicates the motor is bad. The low resistance of my fan motor contradicts this thought.


I may remove one of the fan motors from the parts car to test it in my 1988.

 

[8Mud]

Check the brown wire at the ignition switch connector, The wire/connector has a tendency to melt down. You can get good volt readings, but may not be getting enough amperage and/or iffy contact.

May also be some sort of physical impediment to your squirrel cage fan, Stuff can get caught in the fan blade.

 

[RAVC1]

All good advice and things to consider.

Fixed...at least temporarily.

My blower fan motor is bad. I used my wife's booster pack and wired it directly to the fan motor pigtail so, I did not overload it with current. The fan motor did not respond. One of parts Xj's did so, I exchanged them and have tested the replacement in my 1988. It is noisy so, I will order a new one but, can wait for it to arrive now that it works.

Thanks ! You did it again!!!

 

[b5blue]

I found a leak that had driven everyone nuts for years. The seam for the cowl area leaked on the fuse block. There is a layer of insulating stuff that kinda hides the seam way up above the fuse block area you may need to remove to see it. Water dripping on the fuse block made connections corrode causing weird electrical problems. (Also a rust hole on the floor board!)

 

[Ecomike]

I have 4, 85-89 jeeps. The 85 was the worst. I finally bypassed the Fuse bloc, the ignition switch, the resistor pack and fan speed switch, and put in a new 10 gauge wire and 30 amp breaker/fuse and 30 amp toggle switch, and later I used that to power a 50 amp ford starter relay on the fire wall to run power from the battery to the blower motor through the 50 amp relay. It blows like crazy now

The 87 I just by passed the ignition switch and ran the 30 amp breaker and 10 gauge wire and left the rest OEM with alll new parts, fan speed switch, resistor pack and blower motor. No more problems.

The 89 has never (yet) given me much trouble on the HVAC blower....#4 jeep is a rusted work in progress.....POS so far LOL.

 

[RAVC1]

I checked the main body connector in my 1989 but, not thoroughly enough. I will have time to look at it again tomorrow. I just good image in my head before I take my "mostly functioning Xj" off the road.

I was actually considering seeing what a waterproof MIL spec connector from Amphenol of other...then my car would double in value!