92 Lesabre no heat

3echo9 · #1 12-21-2010, 01:34 PM

No heat, no air movement.

This is an ongoing problem here and I need some help. The daughter drives this car and without heat or defrost she'll be bumbing Dad's car.

I have posted the problem before but I'm having difficulty troubleshooting with the electrical diagram in my Chilton to track down where the fuses are exactly.

It's a 92 Custom with manual controls.

I pulled the dash apart and from what I can tell I have lights to the control assembly and the actuator works. I could see it move when I took the glove box out and moved the temperature selector from cold to warm.

Looking at the wiring diagram it refers to a FUSE 5D 25A and FUSE 5A 10A. I cannot for the life of me find where these are. The fuse box under the dash on the drivers side of the car does not have a Fuse 5 and the passenger side doesn't have one either.

I checked the FUSE 3 30A under the hood and it looked good. Even swapped it with the 30A spare. No difference.

I notice there are references to other fuses such as FUSE 5C 10A (I/P FUSE BLOCK) and FUSE 4 40A (Left underhood fuse block).

I noticed the A/C compressor would cycle on and off every few minutes if that means anything.

I also replaced the blower resister assembly a few months ago.

Thanks for the help.

maxwedge · #2 12-21-2010, 03:27 PM

No blower operation I assume, also no power to the blower motor? There may be a better wiring diagram at autozone.com, repair guides, register and go to chassis electrical.

3echo9 · #3 12-21-2010, 07:14 PM

Thanks, for the tip. Right, I have no power going to the blowers.

I checked out the wiring diagrams at Autozone but they weren't any help. They left out most of the HVAC.

maxwedge · #4 12-21-2010, 07:58 PM

There may be a module, usually on top of or near the evap case under the r/s of the engine compt. mounted near the fire wall. If not look for the blower relay in the main distr. box under the hood.

big white bufflo · #5 12-21-2010, 09:42 PM

i have a 92 limeted with duel zone my blower moduel is located belowe the blower follow the wire down it will go to the blower resistor then there will be wires coming from the fire wall those should have power if all fails run a switch to it thats what i did for a long time till i figured my trouble out good luck

3echo9 · #6 12-21-2010, 11:33 PM

Quote:

Originally Posted by maxwedge

There may be a module, usually on top of or near the evap case under the r/s of the engine compt. mounted near the fire wall. If not look for the blower relay in the main distr. box under the hood.

Are you refering to the blower resister assembly? It's near the firewall under the relay panel. I put a new one in around August this year. Is there a way to test it?

HotZ28 · #7 12-22-2010, 01:01 AM

I would suspect the wiring, or terminal @ the resistor as being the culprit. The "92 Custom with manual controls" does not have a blower control module.

3echo9 · #8 12-22-2010, 12:21 PM

OK..pulled the resistor and did a continuity check across all terminals. All checked ok. Will check for voltage on the Dk Blue wire with car in Run and Heat control turned to HI as soon as I can find a new 9v battery. Any suggestions if I find no voltage?

maxwedge · #9 12-22-2010, 12:41 PM

Check the blower switch in the control head and the connector.

3echo9 · #10 12-22-2010, 05:53 PM

I checked voltage at the blower resistor with car in run...got nothin'.

Checked for voltage at Fuse 3 30A underhood at the fuse block marked A/C on the box..supposed to be hot at all times. I got nothin'.

Checked Fuse 17 (inside-driver) got 10+- volts with car in RUN and 0 when off.

Should there be power at the Control Assembly and if so which wire? I checked the brown wire and got nothing.

maxwedge · #11 12-22-2010, 07:50 PM

Should be a red or orange wire at the control head that is powered. You need power at the fused circuit before you go any further.

3echo9 · #12 12-22-2010, 08:56 PM

Can you expand on where the fused circuit should be? I'm puzzled by the 30A fuse under the hood that's supposed to be hot at all times. Where is this fuse supposed to draw it's power from? There are red lines running behind the fuse that lead to bundles that disappear into the firewall on both driver and passenger sides.

maxwedge · #13 12-23-2010, 08:37 AM

Need some kind of wiring diagram for this are you sure autozone.com does not have this? I found this http://www.autozone.com/autozone/rep...96b43f8038fbb4, a fusible link at the starter harness feeds that circuit in the fuse box, first try direct power to in side of the fuse see what happens.

3echo9 · #14 12-23-2010, 10:58 AM

I poured over those schematics and they don't address the climate control system very well. They only vaguely mention the blower motor and resister with descriptions like "to fuse"...which fuse???

HotZ28 · #15 12-23-2010, 11:01 AM

There is a black wire going direct from the battery positive (+) terminal to the under-hood fuse/relay panel. There should be a 60 amp # 2 fuse in the panel for that wire. Check the 60 amp fuse first, of course if you don't have power on that fuse, none of the rest would have 12v. FYI, here is a layout of the relays in that panel, along with the blower motor/resistor schematic and main fuse panel feed from battery .

Black wire from battery to fuse/relay panel

Blower motor (with resistor) schematic

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