[Jason Malibu]

Hi, guys

My car is 2005 malibu LS,3.5L. My block heater wire had been chewed off in the middle by some small animals. I got it reconnected last year. When I used plug-in last winter, Some wield things happened. I can start the car but the temp gauge not working. Once I got to company, turn off the engine. It won't start again. But everything works well after work(the engine is cooling down and no pluging in). It happened three times during the winter.

Could anybody give me some clew or advice. I really appreciate it

 

[Starship]

Critters don't usually chew on single things and thus you probably have additional wiring damage. I'd give it a once over visually, both front and back side of the engine, and then go from there.

 

[Jason Malibu]

You're so right. I had got several other wiring damage. I got them repaired by dealer except the heater block wiring.

But the situation does not happen all times. That's hard to say where the problem is?

 

[Jason Malibu]

Critters don't usually chew on single things and thus you probably have additional wiring damage. I'd give it a once over visually, both front and back side of the engine, and then go from there.

I'll check the engine around!

Thanks and have a good night!

 

[Starship]

Intermittent problems are a bear to troubleshoot. If I were you, I'd get a kit together (a digital multimeter, alligator clips, wires, etc.) and carry it in the car. Then, the next time it happens, hopefully I'll have everything to tackle the problem on the spot. Also, I'll need the printout of the wiring diagrams for the ECT sensor circuit and starter circuit:

http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va225116.pdf
http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va200242.pdf

 

[Jason Malibu]

intermittent problems are a bear to troubleshoot. If i were you, i'd get a kit together (a digital multimeter, alligator clips, wires, etc.) and carry it in the car. Then, the next time it happens, hopefully i'll have everything to tackle the problem on the spot. Also, i'll need the printout of the wiring diagrams for the ect sensor circuit and starter circuit:

http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va225116.pdf
http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va200242.pdf

thanks a lot

 

[Starship]

You're quite welcome. Let us know how it turns out (it's always nice to hear what worked).

 

[Jason Malibu]

You're quite welcome. Let us know how it turns out (it's always nice to hear what worked).

I found it

QUESTION — Recently some of my co-workers have had problems with the GM temperature-sensitive block-heater cord ends. All situations included standard electrical replacement ends installed on the cords after the original end was removed. Apparently the original end has a temperature-sensitive switch in it that prevents power transfer above -18 degrees. The cord is also tied into the onboard computer system at the heater. Replacement of the original end will cause the motor to operate poorly, set engine codes, etc. Apparently the code can be bypassed, but not permanently. What can be done to eliminate this problem?

ANSWER — Our seemingly extra-cold winter temperatures this year are causing more of a problem with these block-heater cords than they did in the past. The factory block-heater cord end turns off above –18 C. If a regular plug is installed — or because the factory plug, outside the engine bay, cannot track the engine’s temperature as the block heater warms it up — the engine temperature gets too warm and codes are set by the engine computer because of a wide temperature difference between the outside air temperature, sensed by the air intake temperature sensor, and the coolant temperature. The best fix is to install a factory block-heater cord and clamp the plug-in end onto the top rad hose. Use a short extension cord to run out to the front of the vehicle. This will keep the engine temperature within the proper range.
External timers and temperature-sensing cords will also work, but the trick here is to not get the engine too warm. By the way, the factory block-heater cord isn’t connected directly to the engine computer. If it isn’t working the way it was designed, the problem is detected by the computer comparing temperature-sensor inputs.

 

[DrivenDaily]

Dang, why can't they just make it simple? Some of the changes the engineers have made are actually a step backwards. Like the brake light switch. It's no longer a simple switch. Instead it's a rheostat or potentiometer (fancy for volume control) and the computer has to detect the movement and/or speed of movement to decide what to do. What??? Just to signal a simple braking? Yeah, I know it's also tied to the ABS, etc., but now the brake lights take longer to energize than before. Backwards!

I can see that having the block heater design is good IF the device is used as designed, AND if it never has an issue, AND if ........ But if all ya wanna do is warm the engine so it isn't so freaking cold when you start it, what's the matter with just putting the equivalent of a 60-watt bulb under it? With the hood shut it's gonna be warmer than if it wasn't heated at all, and it's definitely not gonna be frozen!

Simple solution. (At least in my mind!) And it doesn't even have to be part of any PCM or BCM or other system. It just needs to work. Simply. (I seriously doubt anyone's gonna drive off with it still plugged in. But if they do there's a fail-safe: the cord will be yanked outta the wall before they get too far!)

Ok, I'll get off my soap box now...

 

[Jason Malibu]

yes, I agree. this kind of devices just need to work. there is no need to make it complicated. if they really wanna improve it, they could add a timer or something like that in the cord..............I don't know.

i decide to buy an oil pan heater instead of original heater. i'm afraid of it now.....

 

[Starship]

Thanks for the update. It sounds like a case of the PCM sanity-checking sensors against each other. In the case of a significant disparity between the temperature sensors, it obviously can't determine the correct air fuel mixture. The short answer seems to be to use the genuine GM cords instead of making impromptu repairs.

 

[Jason Malibu]

Thanks for the update. It sounds like a case of the PCM sanity-checking sensors against each other. In the case of a significant disparity between the temperature sensors, it obviously can't determine the correct air fuel mixture. The short answer seems to be to use the genuine GM cords instead of making impromptu repairs.

Eventhougu you use GM cord, the sensor inside doesn't allow you to plug in at the temp warmer than -18C. Otherwise, the symptoms like mine might happen.