Limp mode 172 bit with a twist. HELP!

[ADVOCULTMOTORSPORT]

Hi guys. I am quite new to this car but been building cars for many years so I am looking for advice and not “take it to my mate mad Jeff, he is a wizard”

so it’s a 172 and keeps going in to limp mode. If I start it with the brake pedal depressed it clears the electrical fault light and allows me to rev pas 3k. But! It idles at 2200 and when I brake the rear fog lamp on the dash comes on slightly and the revs drop back down to 1k

has anyone had this strange combination before? And do you just suggest cleaning the white plug under the fuse box in the bay and hope for the best?

 

[bloke]

clean the usual suspects first. fog on the dash is bad connection on earth on the rear light connector.

 

[ADVOCULTMOTORSPORT]

clean the usual suspects first. fog on the dash is bad connection on earth on the rear light connector.

Great I’ll start there. Being very new to these cars can you point me in the direction of the usual suspects?

 

[bloke]

everything in the fuse box under the bonnet and throttle body plug just about covers it. reset brake light switch,never had to do this myself but plenty of people say it needs doing.

 

[william84]

Back lights brought my foglight indicator on dash with bad earth.
My back lights were like a disco

 

[ADVOCULTMOTORSPORT]

Thanks for the pointers guys.

 

[Rojer]

I had the famous fog light on the dash issue when depressing the brake pedal. I cleaned both the earths but still happened. When i took the rear lights out it was clear all the wiring and connectors were corroded. Got a new lamp panel with the wiring connector and enough wires to solder onto the existing loom and job done. I also had to replace my brake light switch previously, but i just removed and fitted, never did any special procedure.