Hey guys! First post as I have soured the internet trying to find what I did wrong to my car to no avail, so I'm hoping someone here can help.

I got the dreaded dex-sludge in my 03 blazer's radiator, etc. so I just spent all weekend replacing the radiator, upper and lower rad hoses, water pump, thermostat, both heater hoses, heater core, and overflow tank. When I went to start the car for the first time, it started and ran fine, but for some reason the speedo, tach, fuel level, temp, interior lights, radio, wipers and A/C controls quit working all at once! I don't think I missed any harnesses during reassembly, so I'm not sure what's going on. I did have to disconnect the purple plug at the BCM, but I'm not sure if that one plug would control all that. Any suggestions?

Thanks.

 

did you reconnect it after you were done? check your fuses to see if you blew one

 

I'm sure I stuck it back in, but maybe I didn't stick it in far enough to engage the pins??? I didn't check all the fuses, but I did check all of the ones that I thought would be related to the issue (like RDO/BAT, cluster, gauges, etc.) I checked about 10, but all looked OK. WOuld haveing the purple plug disconnected cause all of those problems?

Interesting development - Ijust messed with it some more and when I push the dome override 4 times quickly, the interior lights, speedo, and tach start working again. 4 more times and the speedo, tach and interior lights go off, but the temp and fuel gauges start working. 4 more times and temp and fuel go off and speedo, tach and interior light come back on. Each 4 pushes alternates these back and forth. However, now the automatic headlights won't go off and must be turned off manually.

Still no radio or blower motor.

Do I have a gremlin living in my dash?

 

Sounds like an ignition switch problem to me.

 

Started disassembling the dash today and immediately found a 4 pin connector that I missed reconnecting behind the headlight switch/parking brake. Plugged it in and all was fixed! Not sure how those 4 wires could affect so many different systems, but apparently they do. If I ever have to disassemble my dash again, I think I'm going to flag all of the harnesses with some kind of neon something so I can easily find them again. Thanks to the forum for the advice!

 

Were all of the wires black? If so, it was a ground splice pack.

Glad you found the problem.

 

They were multi-colored (red, blue, yellow, and something else if I remember correctly). Also, they were BIG; they almost looked like the multi-colored lines running from the A/C control **** to the heater module.

Now on to the next thing. When I test drove yesterday, heat and AC worked well. Then last night, I noticed myself getting hot at a stoplight and turned the AC off and the heat on. The heat blew hot for a few seconds and then started blowing cold. The car did cool off though and get back to normal temperature. When I got home, I checked everything under the hood and there were no leaks anywhere, the heater hoses were both hot, and the radiator was still full. I wondered if the fan clutch had gone out but it appears OK.

This morning it performed flawlessly all the way to work (40 miles) with the AC on full blast never getting over 195 degrees. The heat, however, still won't blow hot. When you turn the **** from cold to hot you can hear the difference in the air blowing behind the dash, so I think the blend door is moving. However, I do remember I didn't put the bolt that you access through the blower resistor hole back in because I dropped it in there and couldn't get it back. Could it be jamming the blend door so it doesn't fully open or close or something?

Sorry for the long-winded post. Just want to make sure I give as much info as possible. Don't know about you guys but it's always annoying to me when my mother-in-law wants me to fix her car and when you ask her what's wrong with it all she can tell you is "it's making noise".

 

did ya recheck the level of antifreeze ya out in? if it looks low jack up the pass side of the truck just a little higher than the drivers side, start putting more antifreeze slowly when it starts to bubble at the top stop pouring let it go down and then do it again, I just did a water pump ,thermo and gaskets and a clutch fan on a friends 95 blazer and shes had no problems since the repair, ya have to get the air out of the system....

 

Your temperature issue could be from a low coolant level (air burped out of the engine and lowered the radiator level) or it could possibly be from a dirty A/C condenser and radiator core (exteriors of each).

 

The radiator and overflow tank are completely topped off. I guess there could be an air bubble in the system (specifically in the heater core since there's no heat anymore) but I did fill it up on an incline. I'll try jacking up the passenger side and see if that helps.

The condensor is about 95% clean with a few stray bugs on it. The backside of it is real clean and the radiator is new. SInce I have an entirely new cooling system I'm not sure what could cause me to start overheating. The only culprits I can think of are a stuck closed thermostat (if this is the case it has since reopened since it hasn't happened again) or a bad fan clutch (since it happened while I was sitting at a stoplight).

I'm wondering if there was enough sludge left in the block and heads to clog up the heater core again. When I checked the heater hoses one was piping hot and one was warm. If this is the case, I'm going to be really peeved since I just replaced the radiator, both rad hoses, water pump, thermostat, heater core, bypass hose, heater core hoses and overflow tank to get rid of the stuff!!!