So lately I guess I have been paying too much attention to my "new"1972 coupe and when I took my 2000 coupe for a spin around town the last two times my HUD shows nothing in it's display. I have messed with the brightness and the page button and nothing causes anything to be visable. I know that everything else is functioning in the car just fine and I also know that the HUD gets it's sole power and info input from the guage cluster... Any ideas or suggestions of what to look for and where to begin would be greatly appreciated. Thank you.

Sully

 

So you have HUD in your '72 coupe?

 

Oyyyyyyyyyyyyy!

 

Loss of primary power would be my first guess. Start with fuse being used and work from there. Bad connection maybe too.

 

There is a few things that will cause this.

1. Bad HUD (been there, done that)
2. Bad connection to the cluster
3. Bad connection to or bad dimmer control.
4. Possibly bad cluster.

If the cluster has power but no data it will still display -- where the speed is displayed. If the dimmer control is disconnected the HUD goes full dim, or off like your is now. Like you stated, all power if feed through the cluster. If your cluster works you HUD should work, no other fuses or anything in line. Unlikely a cluster power problem but it is possible. The dimmer control does pass across the main cluster PC board, but has no control inside the cluster, just passes through from plug to plug.

First thing to check is to be sure all cable are seated good. Remove the cluster and re-seat all the cables. If it still don't work check the voltage on the plug coming from the cluster to the HUD. It has been along time since I probed that plug but you will have 12VDC+, Ground, Mirror Up, Mirror Down, Dimmer, Data, Data Clock, and possibly the page control. On your dimmer line you should read a variable 0-12VDC as you slide the dimmer control.

One quick check to see if the HUD has power would be to look down in the windshield and try to move the mirror up and down, if it moves the HUD has power. If not, likely a bad connection to the cluster. Those plugs have been know to fall out for no reason.

 

He has listed as owning a 2000 coupe, 1972 Coupe, 1966 Coupe. I think he is saying he has been spending too much time on the 72 and not the 00.

 

I must need to be more specific.... been spending too much time with the 72 and not the 2000 coupe. I was just attempting to be funny by saying the 2000 was becoming jealous and that's why she is acting up with the new HUD problems...

The HUD doesn't have a fuse specific to itself, at least I thought so. It gets all it's power and info directly through the guage cluster...I just hate having to disassemble the dash to get to the one little connector wire harness that is between the guage cluster and the HUD... wouldn't think that it would just fall out... but maybe it is a bad connection... at least lets hope... I don't want to have to replace the HUD unit itself...

Sully

 

Im gonna check to see if the mirror moves up and down .... be right back...

 

when looking into the HUD and at the same time moving the up and down button nothing moves.... no movement from the mirror at all. This is good... probably means that a cable has come loose and that is why there is no power... thanks Speedy... great idea!

Sully

 

Oh, my bad, I thought it would be awesome to see a '72 with HUD.

 

Everytime I drive one of the old cars I keep findinng myself looking for the speed display reflection from the HUD in the windshield....I wish it was there....lol...


Sully

 

Cool, good starting place. It still could be the side cable between the control switch and cluster, or the main cluster to HUD cable. The side cable on the switch end really has nothing holding it in other than the force of the metal connectors. The other cable ends has small tabs on the plastic connectors. HERE is some photos of the side control cable. You might me able to reach up around behind the cluster with your hand and push in on the connectors. There really is not much room under there but with a small arm and hand or remote controlled monkey you might just be able to do it without removing the cluster, but I'm betting not. Clusters are fairly easy to remove. Console, lower dash panel, lower foam holder, steering column bolts, and four cluster screws is about all you need to remove.

Not 100% sure but I think there is still a slight chance of it being a bad HUD even without the mirror moving. But I'm betting it is a cable loose.

BTW: From now on park the 2000 on the other side of the house so it can't see you are working on the 1972.

 

Looks like you guys are on the trail here.

Looks like you got the power question answered. I'm with you on the bad connection being the most likely culprit, especially if this is a retrofit. BTW, nice touch with the logo in a couple of your pics. Going for that "OEM" look, eh?

Sully: let us know what you find.

Robert

 

had local corvette club meeting last night and spent an extra hour afterwards chatting with a guy about his new 1971 that he just got... giving some info and pointers... he has a sweet ride that with a bit of work will be that much more...

but will do on lettinng you know what the cause is...

thanks again,

Sully

 

went to lunch and the dang thing was working... but then on the way back to the office not working... so I bet one of the plugs has come loose... I'm gonna have fun taking the dash apart...

Sully