: '89 Heater Blower Dysfunction



caddeville89
12-24-10, 09:19 AM
Alright, here we go again...

In my '89, the heater blower will only come on for a couple seconds, then shut off. Makes for a cold ride to work. I tested the voltage between the orange plug on the blower and the ground strap, and there is 14.something volts. But no blower.

"Ok," says I, "let's replace the blower motor." $15 and ten minutes later, same problem. My guess at this point would be the blower relay, but why am I getting voltage at the blower? And where is the blower relay?

ALSO, the buttons on the ECC Module don't always work. Could this be a bad ECC?

sven914
12-24-10, 10:56 AM
It might not be the blower motor. There might be a problem with you ECC control head, programmer, or power-module.

The following diagnostic tree is for the blower not being functional at all, but it may still apply to your intermittent problem.

http://carphotos.cardomain.com/ride_images/3/3489/1/33720000168_large.jpg
http://carphotos.cardomain.com/ride_images/3/3489/1/33720000169_large.jpg

I don't have time right now, but later I can check my service manual to see what it says about an intermittent blower.

caddeville89
12-24-10, 06:34 PM
Yah I followed that chart and ended up with "Repair the Orange and Black Wire. I visually inspected it at the power module and at the programmer, and it looks fine. The only other place where there is a junction is where it comes in the firewall. So far, this is really frustrating. Add to that, I bought a blower motor and a heater relay that I apparently don't need.

One funny thing that I noticed, is that if I ground out the heat sink on the power module, the blower comes on right away. I am guessing this is a normal function of it.

Robin Banx
12-27-10, 01:50 AM
The the blower control module in those cars '81 through '89 are notoriously troublesome. I have had three or more of them go bad over the years. I'd try for a used one from a car that has been recently on the road.

Cheers........R.

sven914
12-27-10, 02:07 AM
I just got a chance to check my FSM, and there isn't any diagnostic information for this problem.

Perhaps providing some more information might help me or someone else narrow down possible causes.

What are your ECC settings (temperature and mode) when this happens?

Is the engine at operating temperature?

Does the blower work with the defrosters? Or do you experience the same issues?

If you set the temperature for 60* or 90*, does the blower function normally?


Being that the ECC, as you said, doesn't work all the time, the control head is probably the problem. But another cause might be the temperature sensor not reading correctly, and assuming the passenger compartment is warm.

caddeville89
12-27-10, 02:18 PM
The chart somebody provided here is the same as the chart in my DSM. The blower will not come on under any circumstance.

However, if I touch the ground (tan) wire to ground, or ground out the heat sink on the power module, it will immediately come on.

As an update, today I went to pull-a-part and got a new power module, programmer, and head unit. All this cost about $40. After swapping these in, the damn blower will still not come on! I am going to go through the fuses and see if that helps the problem, but right now I am pretty frustrated.

sven914
12-27-10, 03:53 PM
Ok... That rules out the temperature sensor. Setting the ECC on Defrost, 60*, or 90* would automatically force the blower on high, despite temperature.

The TAN wire is connected to the power module's control for the blower operation. When the Power Module receives the signal to turn the Blower Motor on, the Power Module supplies ground to the TAN wire. Maybe the Power Module is not getting an input signal from the Programmer or the Control Head.

If you can, check for continuity in the ORN/BLK wire that runs between the Programmer and the Power Module. If there isn't a lot of resistance in that wire, check the continuity in the BRN/WHT and GRY wires that run between the Control Head and the Programmer.

caddeville89
12-27-10, 05:19 PM
Yah, it was a bad ground. The ground wire that goes from the power module to the bulkhead needed cleaning. After $65 worth of parts I can't return, that is what it comes down to. Will post those parts in the wanted section.

sven914
12-27-10, 05:36 PM
I would have eventually suggested that...

caddeville89
12-27-10, 05:48 PM
Yah I feel like a complete idiot. I unscrewed that thing a couple times too to remove the power module. I guess I figured that since it was intermittent, it must have been a switching problem. D'OH!

sditmer
01-20-11, 07:45 PM
Yah, it was a bad ground. The ground wire that goes from the power module to the bulkhead needed cleaning. After $65 worth of parts I can't return, that is what it comes down to. Will post those parts in the wanted section.

I have an '87 Brougham with the same issues. A bad decade for GM climate ctrl. Anyhow, my fan does work when TAN is hot-wired to ground. I also followed the above chart down to the jumper on the programmer pin T to M - no fan. I've not tried continuity on O/BK from programmer to pwr module. The CCM appears to be working properly - all buttons when pressed make their little lights come on and the temp change does affect air temp with the hot-wired blower on. But none of the vacuum functions appears to be working and the air diversion for defrost does not work, which appears to be an electrical function of the programmer. Would this be the final N/G indication on the programmer?

I don't want to waste money on parts that I don't need (who does?) and if those parts are still available I may want to talk to you.

sven914
01-20-11, 08:00 PM
How did you hot-wire the blower to come on?

The air is directed to the different vents by vacuum powered doors. The default when the vacuum is disconnected is defrost. On the passenger side of the fire wall, there should be a round vacuum canister; make sure all of the hoses are connected and are not split or leaking.

cadillac kevin
01-20-11, 11:21 PM
just wondering, is it normal for the heat to not come on for a few minutes in the winter if the heat is on max and on floor vent. If I turn the engine on, and turn the heat to come out the vents, nothing will come out of the vents for about 3 to 5 minutes, but if I turn it to defrost, air comes out (although it's ice cold air for about 3 to 5 minutes.)

sven914
01-20-11, 11:48 PM
The ECC has an override function that will not allow the blower to turn (unless in defrost) until the engine has reached 150 degrees. One way to make it come on is to hit defrost, then AUTO, and the ECC will be tricked into giving you HI blower operation until the in-car temperature sensor tell it to stop.

sditmer
01-21-11, 01:23 AM
How did you hot-wire the blower to come on?

The air is directed to the different vents by vacuum powered doors. The default when the vacuum is disconnected is defrost. On the passenger side of the fire wall, there should be a round vacuum canister; make sure all of the hoses are connected and are not split or leaking.

To get the blower on, I used the blower trouble-shoot test with a switch. The blower always gets 12v through its +, and gets - through the TAN wire coming from the power control module - it's the other end of the TAN wire with a six-pin connector and ground wire. The fan speed is controlled by the 'amount' of ground to the fan thru the TAN wire, regulated by the power module. Since its the middle of winter, until I sort out the actual problem, I disconnected the TAN wire from the power module and using 10g primary wire, ran a line into the driver's side, used a 25a switch and then to a ground under the dash. At least this way I have hot air blowing. Just remember to turn off the fan when you leave the car or you'll be dealing with a dead battery next.

I've got vacuum at the canister and into the programmer (behind the glovebox). Took the programmer apart and by jumping the vacuum ports with a little hose, I got the air recirculation flap to move and the floor-to-dash flap to move. I could not get the defrost flap to move but I saw a pair of wires from the programmer going to the point where the accordian flextube from the defrost vent goes to the firewall, so I thought maybe it was a solenoid setup.

Oh the price of luxury!

sditmer
01-28-11, 05:57 PM
I've been dealing with my '87 Brougham RWD heating A/C issue as well. My issue stemmed from a fan that wouldn't come on, but the blower functioned in the direct-grounding test. My problem was trying to determine if the issue was the power module on the fan housing or the programmer. I did the performance steps but still no success. The ECC seemed ok as all the lights and digital readout were working fine. I was speaking with a mechanic-friend of mine who said in reference to the power module on the fan housing, "I've replaced countless numbers of these, and only a small few programmers. Have you rapped on it yet?" I laughed, but he said "try it." So I did, and darned if the fan didn't start working again! But, in trying to trouble-shoot the programmer, I messed up the vacuum lines on the INSIDE. I wrote done the colors but lost my paper. Does ANYONE have info on the vacuum lines inside the programmer? Also, one of those lines had a small metal pin blocking airflow in it that could not have come through any of the nipple orifices. Is it supposed to be in there?

Thanks to anyone who can help.

caddeville89
01-28-11, 09:51 PM
Oh man, yer gunna make me crawl in there and figure this out ain't ya... Well, I don't have the car right now, but I would get a DSM.