Forward Lamp Harness/Engine Harness connector

[1970Monte]

Happy Saturday!

So I'm installing the idiot light to gauge conversion and have to add some wires to the forward lamp harness connector. Please see the pics below, not sure what happened here but I am assuming that both sides should be relatively clean instead of black gook? Not sure if this is dielectric grease or leaking brake fluid from the past or something else. I think I am going to try brake cleaner on this on both the firewall side and the plug side. Any suggestions here?

 

[cbolt]

mine looked about the same when I took it apart 20 years ago, but I didn't clean it up. I replaced both harnesses. 

[cny first gen 71]

I would use the electronics cleaner, leaves no residue I believe crc makes it.

[cbolt]

9 minutes ago, cny first gen 71 said:

I would use the electronics cleaner, leaves no residue I believe crc makes it.

I don't know that electronics cleaner will even touch that stuff. As I recall it is quite tacky and thick. Gooey

[bob 71]

i use brake clean on things like that. not crc red can. leaves a film/oil residue

[cny first gen 71]

46 minutes ago, bob 71 said:

i use brake clean on things sorry that. not crc red can. leaves a film/oil residue

I thought just the opposite,  sorry if I gave wrong information 

[Scott S.]

The black goop was installed as a weatherproofing for the electrical connections. It's very "gummy", so the more of it you can pick out without a chemical cleaner, the easier the rest is to remove. 

[TheBMan]

I replaced the engine harness in my '70 and not only did it have that goop on the firewall terminal mount, the company that supplied the new harness, https://www.lectriclimited.com/, provided new goop. It's to prevent fumes from entering the passenger compartment from the engine bay and it also provides weather protection. You should absolutely use the stuff when you do your repair or replacement.

[1970Monte]

I guess the goop broke down on one side but not the other; I feel like it's a miracle that there were connections being made in there that weren't causing intermittent problems. I am through most of this now but several of the wires that got sent with the gauge kit are way too short and I'm having to splice them. 

Thanks everyone for the insight.