The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Strange HVAC operation..... If you need to replace connectors this may help

speedygonzales · 04-30-2018, 10:09 AM

For those who don't want to read the whole thing here is a summary:

Either your blower motor only comes on high speed or you have to beat on the controller to make it blow (usually at high speed only)

The blower connector could be bad on the back of the controller

Using the part number for the connector, google a replacement.

You can add a second supply wire so the entire supply current is not on just one pin.

Now for the details.

If you own a 96 – 2000 with a HVAC controller that looks like this:
http://s1371.photobucket.com/user/St...tml?sort=3&o=1
Pay attention. Connectors of all sorts are getting weak or corroded and high resistance is the result. When high(er) current is involved, high resistance equates to high heat. Melting will occur.

Here is a photo of the fan connector on the rear of the controller
http://s1371.photobucket.com/user/St...tml?sort=3&o=2

Here is the harness connector
http://s1371.photobucket.com/user/St...tml?sort=3&o=5

Another view
http://s1371.photobucket.com/user/St...9rncn.jpg.html

So the symptom is you either have to hit the controller to make the fan come on or it usually only runs on high.
Yeah I know everyone will say it’s the blower resistor. NOPE not in several cases. You know the controller is having problems when you have to beat on it. Don’t be fooled by thinking because the blower only runs in high the resistor is shot if you have to hit the controller to get it to come on. Address the problem with the controller first. Chances are good the resistor is fine. If you just replace the resistor first, you are probably throwing money away.

In my case the power coming to the controller was the problem. The black wire got so hot it melted the connector.
Here is the replacement connector and it’s pins. It uses pigtails that have to be soldered in.
http://s1371.photobucket.com/user/St...ndsdr.jpg.html

Sorry it's small

Here’s the lowest cost alternate you can find.
https://www.ebay.com/itm/New-8-Way-F...72.m2749.l2649

Now you can be proactive so this won’t happen to you. You can add a second supply wire so the entire current isn’t going into only one pin. Look at the connector back picture and you’ll see the orange and black wires. There are 2 blank connections unused. If you get the connector kit, splice another pin into the supply line and place the other pin on the far end of the row where the orange wire is opposite the green wire. Look at photo of the burned backside connector on the controller.

If you look at the controller in your vehicle you will see 2 pins are connected together. It’s hard to tell from that photo but there is a unburned pin on the bottom left. Then the melted pin next to it. Then a blank spot next space over to the right. Then a pin on the far right bottom location connected to the burned pin.
The factory chose not to connect to the far right pin, instead only using the second one on the left. I chose to tie into the same wire (black) bringing the second connection to the far right pin. This will alleviate the entire current to the fan motor from going through only one pin. Which obviously is on the hairy edge of disaster.

If in the future you are searching for connectors, you will need the GM part number for them. Fortunately the part numbers are in the factory service manual.

Part number for this connector is 15306189 and you may notice that it’s used in several locations throughout the vehicle.

One last note: These controllers are going up in cost every day. The more reasonable ones are $100 now. The longer you wait to address this issue, the more you're going to pay.

Also, there are several ways to get GM metri-pack connectors. There are kits that contain several. They are expensive.

Don't forget to use google once you have the part number for the connector. I don't usually use Ebay but in this case the least expensive was there.

Incidentally this same connector through the local auto parts stores ran anywhere from about $35 to $180. Yeah I thought I had a bad connection when I asked the guy "did you just allow the words one hundred and eighty bucks to come to out of your mouth"?

04-30-2018, 10:09 AM	#1
speedygonzales Registered User Join Date: Jan 2006 Location: Smithfield, VA Posts: 1,501	Strange HVAC operation..... If you need to replace connectors this may help For those who don't want to read the whole thing here is a summary: Either your blower motor only comes on high speed or you have to beat on the controller to make it blow (usually at high speed only) The blower connector could be bad on the back of the controller Using the part number for the connector, google a replacement. You can add a second supply wire so the entire supply current is not on just one pin. Now for the details. If you own a 96 – 2000 with a HVAC controller that looks like this: http://s1371.photobucket.com/user/St...tml?sort=3&o=1 Pay attention. Connectors of all sorts are getting weak or corroded and high resistance is the result. When high(er) current is involved, high resistance equates to high heat. Melting will occur. Here is a photo of the fan connector on the rear of the controller http://s1371.photobucket.com/user/St...tml?sort=3&o=2 Here is the harness connector http://s1371.photobucket.com/user/St...tml?sort=3&o=5 Another view http://s1371.photobucket.com/user/St...9rncn.jpg.html So the symptom is you either have to hit the controller to make the fan come on or it usually only runs on high. Yeah I know everyone will say it’s the blower resistor. NOPE not in several cases. You know the controller is having problems when you have to beat on it. Don’t be fooled by thinking because the blower only runs in high the resistor is shot if you have to hit the controller to get it to come on. Address the problem with the controller first. Chances are good the resistor is fine. If you just replace the resistor first, you are probably throwing money away. In my case the power coming to the controller was the problem. The black wire got so hot it melted the connector. Here is the replacement connector and it’s pins. It uses pigtails that have to be soldered in. http://s1371.photobucket.com/user/St...ndsdr.jpg.html Sorry it's small Here’s the lowest cost alternate you can find. https://www.ebay.com/itm/New-8-Way-F...72.m2749.l2649 Now you can be proactive so this won’t happen to you. You can add a second supply wire so the entire current isn’t going into only one pin. Look at the connector back picture and you’ll see the orange and black wires. There are 2 blank connections unused. If you get the connector kit, splice another pin into the supply line and place the other pin on the far end of the row where the orange wire is opposite the green wire. Look at photo of the burned backside connector on the controller. If you look at the controller in your vehicle you will see 2 pins are connected together. It’s hard to tell from that photo but there is a unburned pin on the bottom left. Then the melted pin next to it. Then a blank spot next space over to the right. Then a pin on the far right bottom location connected to the burned pin. The factory chose not to connect to the far right pin, instead only using the second one on the left. I chose to tie into the same wire (black) bringing the second connection to the far right pin. This will alleviate the entire current to the fan motor from going through only one pin. Which obviously is on the hairy edge of disaster. If in the future you are searching for connectors, you will need the GM part number for them. Fortunately the part numbers are in the factory service manual. Part number for this connector is 15306189 and you may notice that it’s used in several locations throughout the vehicle. One last note: These controllers are going up in cost every day. The more reasonable ones are $100 now. The longer you wait to address this issue, the more you're going to pay. Also, there are several ways to get GM metri-pack connectors. There are kits that contain several. They are expensive. Don't forget to use google once you have the part number for the connector. I don't usually use Ebay but in this case the least expensive was there. Incidentally this same connector through the local auto parts stores ran anywhere from about $35 to $180. Yeah I thought I had a bad connection when I asked the guy "did you just allow the words one hundred and eighty bucks to come to out of your mouth"? __________________ 99 Z71 (98 body style) Pride and joy Last edited by speedygonzales; 04-30-2018 at 10:28 AM.