Today i pulled the centre dash to see why i had a constant Check engine light

So i tested the black/pink centre dash harness against the battery and the harness ground and it was the same, so harness ground is fine.

Dash lights work but i have a flickering check engine light, rear of mine looked like this


And out


Question 1

This was plugged into my check engine slot, its not even got contacts on it to be activated by the board its just powered by grey and pink wire coming from a loom that goes along the handbrake / shifter tunnel area and then up into engine bay. The wires are not long enough to go in top of the vents to shine on AC control so have no idea what its for ???



The radio wire for "illumination" is spliced into it..


Question 2 - As for Air con
I find a broken vacuum line


It is the Black #1 that tees off to the yellow solenoid behind glove box and then out the engine gromit where it was not connected to anything... instead i find a larger hose connected to the 2 way valve (it spilts off on the left T heading back wards, far one on the left). It comes back inside cabin and i guess is supposed to be connected where the broken black vacuum hose is on the heater control thing with the other blue, green, tan lines... so i connect it and now i get a hissing noise when the AC is off and turned on. It only goes away on vent, dist or normal... Any ideas???

 

Anyone ? I have a hissing AC, Tested Heater blower rely, is fine. My heater works fine , from all ports and doesnt hiss. AC hisses and doesnt work at all ...

 

What year is your car? That would help a lot. I have an 82 and my check engine light is not wired up as yours, my bulb is mounted similar to the Seat Belt bulb just above it.

The A/C control uses engine vacuum to open the upper vents for Vent and A/C. Does your hissing noise happen at Max A/C or regular A/C or both? There is a door in the passenger panel that is vacuum operated to open or close depending on the A/C setting. This could be your issue with the hissing noise.

 

I believe that's the light for the PRNDL

 

apparently its a 1980
https://www.corvetteforum.com/forums...t-1980-c3.html

 

Thanks for teh replies

1980, it happens along the range except for VENT, HRT, and the defrost rear window one. But from MAX to Normal there are sections that it will not hiss... i can take the rubber part of the selector that has the VAC source line and block it with my finger and no leaks. i put it on the black selector with the 4 /5 nipples and it will hiss at certain locations.

The passenger side actuator thing i dont know if it even works, how can i test this ??

As for the light , what is PRNDL ?? It is not the light going to the automatic gear selector as thats in there, it will not reach the AC light hole at teh top of the vents so It has constant power to it also..

 

There is a vacuum line that goes to the door in the passenger side kick panel. You can test it with a vacuum pump. PRNDL is the indicator for the transmission, but on Vettes its PRND21. I'm confused why you have a check engine light if it's an 80 vette though. I didn't think they had computers in them until 81

 

It's California model that's why computer in the 80.

It's not the prn123 indicator as that light is on other side. This light is not very long and is on the wiring loom running down the drivers trans tunnel

 

So to check it do I take the line off the actuator and see of it opens or should I move the selector to a position that should activate the orange vacuum line ? Anyone know what position should open the passenger vent and does it have anything tondo with ac ?

I can't hear and clutch kick any that I have read others talk about but ok not sure what to look for

 

Have you tried jumping the DLC connector terminals 1 +2 and see if the bulb flashes a code 12 and maybe another code since it's on constantly?

 

What are 1 + 2 DLC terminals ?the printed circuit board where bulb screws into or 1 + 2 as per the plug black =1, green = 2 ??
And when you say jumping applying 12 v to the printed terminal and ground the other ? Which do you ground , the black and 12 v to green ? and how to check for any codes ? With the standard bulb in like the blue terminal plug it doesn't flash but the other bulb flashes on and off randomally

 

there's a connector under the ashtray with 4 terminals in it. with the key on you should be able to touch a screwdriver across the two terminals farthest to the right and the check engine light should start flashing codes.

EDIT, it's actually 5 terminals and the two you need to jump are labeled D + C

 

ok thanks i will give it ago.
Link doesnt work, i assume its this
http://www.elcaminocentral.com/showthread.php?t=27196

Thanks

 

This is the harness, the I/P what ever that stands for. See 12H what ever that is, page or diagram in AIM? would most likely show my random light.

Anyone got pics of their AC heater control lamp that goes at the top of the vents as i have nothing there

 

I/P is instrument panel.

that light didnt flash when you jumped those two terminals?