I have a 1986 rx7 n/t. The light cluster on the dash fades in and out. When I notice my clock is not working, I can also try to beep my horn and the horn wont work. If I come to a stop it comes back. Is this a grounding problem>? How do I fix it. Also the alternator symbol saying , Charge, comes on..altenator working fine.

 

are you talking about the idiot light cluster on the dash or the gauge cluster??

 

sorry...the idiot light cluster.

 

Your clock is not working mostly likely because of cold solder joints in the idiot light cluster. This contains a discussion pertaining to that - https://www.rx7club.com/2nd-generation-specific-1986-1992-17/warning-cluster-teardown-corrosion-other-issues-w-pics-614646/

Your horn may be on it's way out too. I believe it's controlled by the CPU (not sure about S4's) I have no experience fixing that, but I have fixed my clock.

 

I dont think its a problemt wih the connections on the back of the circut board. Whatever it is causes the idiot lights and horn to stop...whenever I go over 40 mph. Im thinking something with the altenator connections but idk.

 

someone have any idea?