1988 GW RESTOMOD

[FSJ Guy]

The A/C will never blow out the floor or defroster. It was an afterthought originally and was never updated through the years. Yes, really.

Check your vac hoses for the HVAC system. They should be hooked up to vacuum through the reservoir ball on the firewall. That may be why you're not getting any heater air flow.

[ProTouring442]

OK, I got both the dash and engine harness redone and put back in. Everything works like its supposed to now... well almost everything.

I fixed all the vacuum leaks, now 4wd works again.

I can't figure out why my HVAC works on everything but vent and heat. The A/C compressor kicks on when you slide the temp select to cold. Also it only blows out the vents, can't get it to blow out the defroster or the floor. It also wont blow hot air. Both heater core hoses get hot so I know its not plugged.

I cleaned the jamb switches on the front doors so now the courtesy lights work on all the doors.

Sounds like an electrical issue on the issue of which ducts it blows out of. When you select "Heat," it should shut the A/C compressor and A/C blower off and turn the Heat/Defrost blower on. Is the A/C blower staying on all the time?

No matter what, heat will never come out of the Vent ducts. Heat can only come out of the Defroster and Heat outlets. A/C can only come out of the A/C outlets. Unfortunately, they are two completely different systems.

Frankly, I scrapped the whole dang thing, but that's a whole different story. If you need anything, I probably have it though.

[GonOvr]

Oh ok. So my system is working correctly except my heater fan isn't coming on. I did take it out today because it was loose. Then I tested it on the battery and it spun right up. I wonder if the resistor is bad. I didn't put 2 and 2 together when I found the 2 separate fans.

Ill check for power out at the heater fan when its on heat.

I fixed the vacuum ball and have vacuum because the 4wd switch works now.

[ProTouring442]

Oh ok. So my system is working correctly except my heater fan isn't coming on. I did take it out today because it was loose. Then I tested it on the battery and it spun right up. I wonder if the resistor is bad. I didn't put 2 and 2 together when I found the 2 separate fans.

Ill check for power out at the heater fan when its on heat.

I fixed the vacuum ball and have vacuum because the 4wd switch works now.

Check to ensure the fan has a good ground too. No ground, no fan! LOL

[GonOvr]

Check to ensure the fan has a good ground too. No ground, no fan! LOL

I disconnected the fan power and ran it to the positive post on the starter relay. It spun up great!

I don't have power going to the 4 pin connector on the side of the heater core box.

I have power on both sides of the fuse.

Since I rebuilt both harness' I know the wiring is good.

[FSJ Guy]

Your HVAC controller could be bad. The "slider" switch that you move from HEAT to DEFROST, etc, is the switch that routes power to the heater blower motor or the A/C blower motor. You can partially pull the HVAC controller out and test the switch. The connector is at the top of the HVAC controller.

[GonOvr]

Where is the blower relay? not the fan speed resistors but the actual relay?

[FSJ Guy]

Relay??? I don't think there is a relay. The HVAC switch switches power from the A/C blower to the heater blower or turns it all off.

I'm not sure what relay your'e referring to.

[GonOvr]

Relay??? I don't think there is a relay. The HVAC switch switches power from the A/C blower to the heater blower or turns it all off.

I'm not sure what relay your'e referring to.

Well I found it, it was behind the headlight switch. I replaced it and it didn't change anything. So I dug a little deeper and found the issue.



Apparently there are 2 different styles of HVAC controllers. I didn't notice the difference until I took it apart.

The one on the left is what was in it and the one on the right is an extra one I had. See the 3 differences?



Now the fans work correctly, A/C fan works on A/C settings and heater fan works on vent, heat, defrost. I still can't get any air to blow out the defroster or heater vents. Pretty sure its a vacuum or blend door problem.

[ProTouring442]

Now the fans work correctly, A/C fan works on A/C settings and heater fan works on vent, heat, defrost. I still can't get any air to blow out the defroster or heater vents. Pretty sure its a vacuum or blend door problem.

Where is the air going?

[GonOvr]

Now the fans work correctly, A/C fan works on A/C settings and heater fan works on vent, heat, defrost. I still can't get any air to blow out the defroster or heater vents. Pretty sure its a vacuum or blend door problem.

Where is the air going?

No where, on high i can't get any air flow. I pulled the fan out yesterday and ran it up out of the box. It produces plenty of wind on its own. I think either a blend door is closed or i have some major blockage somewhere.

[FSJ Guy]

Quite interesting. You've delved deeper in the switch than I have. Makes me wonder which one I have. I have a replacement for mine, too. I wonder if they're the same….

A vac line may be disconnected from a blend door motor or you have A LOT of leaves in the blower motor housing. If you remove the motor, you can peek in and see if the heater door is opening and closing. If you have one of those cheap borescope cameras from Harbor Freight, you can poke it into the assembly and see if you have a blockage there.

[GonOvr]

Just pulled the heater fan back off and it didn't look bad until I looked down the hole with a mirror. I can see a bunch of leaves to the point it can't close the blend door. Also my cable hold down is broken where it mounts to the heater core housing.

[GonOvr]

OK, I pulled the heater core box out and it wasn't as bad as I thought. It had leaves in it but not enough to block flow and the heater core fins are clean. I found out that the blend door behind the heater box isn't opening. I checked the vacuum motor for vacuum and it had none on any setting. Now I need to find out where the vacuum problem is. Im going to pull the switch back apart and check the vacuum board to see if there is a difference there as well.

[GonOvr]

I do indeed have vacuum at the vacuum board on the HVAC switch. I took the switch apart again and this is what I found.



I put the other vacuum board in and presto! Everything works.

[GonOvr]

Also this is what my HVAC controller looks like. I can't find another one like it for the waggys.

[GonOvr]

Found an inline glass fuse above the steering column blown. Changed it out and wouldn't ya know... the cruise started working.

[TUDrewser]

Found an inline glass fuse above the steering column blown. Changed it out and wouldn't ya know... the cruise started working.

I'm going to go check for this in my 90 right now...

[GonOvr]

Started doing a little restoration on the center caps.

[FSJ Guy]

Also this is what my HVAC controller looks like. I can't find another one like it for the waggys.

I think the first version of the XJ's had a similar HVAC controller.

Good find RE the cruise control. That's a common reason for cruise control failure.

EDIT: Stupid typos….