1969-1971 Horn Relays 1115890 & 1115889

[David L.]

Based on my research the 1115890 horn relay was original equipment on at least the following models:
mid & late 1969-1970 Corvette
mid & late 1969 Camaro (after 03/03/1969)

The 1115889 was original equipment on at least the following models:
1970-1971 Camaro
1970 Chevrolet
1970 Chevelle
1971 Corvette

My 1970 Chevrolet Parts Catalogs (Sept. 1970, Nov. 1970, Jan. 1970 & Oct. 1970) list GM # 1115890 for All 1970 Chevrolet Models.

According to Chevrolet Parts History GM # 1115890 was replaced with GM # 1115889 in June 1971.

According to my Warehouse Classification Booklet - Chevrolet Service Parts & Accessories (Sept. 1969) both horn relays, 1115889 and 1115890 are listed. The 1115889 relay is listed for only Chevrolet models while the 1115890 relay is listed for Chevrolet, Oldsmobile, and Pontiac models.

My question is why were 2 different horn relays used during the 1970 production and what is the difference between them?

Enclosed is a couple of photos of my NOS 1115889 horn relay with a metal cover embossed "Delco Remy", a black plastic bottom part, and stamped "889" on one of the metal terminal parts.

After just looking on Ebay I found 2 NOS 1115890 horn relays and the bottom part was metal with a "890" stamping.

[Jack H.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

They're functionally equivalent in terms of form/fit/function. And, you can kick in the '68-only 1115862 to that pool of install and work-alikes.

The differences are all gossamer construction details. The 862 relay has a metal mounting stud and translucent plastic insulating 'skirt' surrounding the electrical terminals. That translucent plastic was known to dry out, flake and chip based on heat exposure...

The 69-70 '890 relay improved the plastic insulating skirt by going to a thick black plastic. The '71-only '889 relay was a further cost improvement in that it used the black plastic insulating skirt and eliminated the metal mounting stud. The same black plastic material used to form the insulating skirt served as the mounting stud...

Also, it's not a good idea to use the P&A Catalogs to reference what parts were used on what year cars... Service was it's own profit center and they REALLY focused on how to minimize the number of parts in inventory to service the installed base.

So, if there were running changes at the factory, service would tend to warehouse ONLY the latest version of a given part with the broadest applicablity. Look at the JG books for what parts were factory original to what cars.

[David L.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

Jack,

According to the 1970 Camaro, Chevrolet, and 70 Chevelle assembly manuals all show the 1115889 horn relay. I assume the 70 Corvette Assembly Manual shows a 1115890 horn relay. I do not have a 70 Corvette Assembly Manual but I do have a 69 Corvette Assembly Manual and it shows a 1115890 horn relay with a reference to the revision record which is not readable. I assume the early 69 Corvette used the 1115862 based on other research.

Here is my question. Would you have any idea why some 1970 Chevrolet models use the 1115889 horn relay and others use the 1115890 horn relay during the same production year since the 2 horn relays were essentially the same?

Last night I saw a NOS 1115890 horn relay on Ebay with a metal bottom section stamped "890". Based on what you said I assume the factory installed 1115890 horn relay on a L69-70 Corvette had a plastic bottom part, correct?.

Dave

[Jack H.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

Don't presume, go get the AIM and check it out IF that's the info you're after... What Camaro, Chevelle, Nova, Etc. did is not necessarily what Corvette did. Remember, Corvette was a pretty low volume platform then and now...

I recited the PN vs. model year designations that are 'taught' by the various NCRS JG books for Corvette use:

1968 = '862
1969-70 = '890
1971 = '889

I also recited the physical construction differences of these three horn relays that are 'socket' compatible. What more do you want?

[Chuck S.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

Don't presume, go get the AIM and check it out IF that's the info you're after... What Camaro, Chevelle, Nova, Etc. did is not necessarily what Corvette did. Remember, Corvette was a pretty low volume platform then and now...

I recited the PN vs. model year designations that are 'taught' by the various NCRS JG books for Corvette use:

1968 = '862
1969-70 = '890
1971 = '889

I also recited the physical construction differences of these three horn relays that are 'socket' compatible. What more do you want?

The 70 AIM, UPC 12 Sheet A6, shows the 1115889 relay. No revisions indicate any relay change during 70 model year. Unfortunately, my relay is not available to examine.

[Jack H.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

For right or wrong, Chuck, the current JG book defines the horn relay that's correct for 1970 as being the '890 and not the '889. There are hand sketched pix to distinguish '70 from '71 and '72 with the '70 relay clearly called out as having a metal vs. plastic mounting tab...

Of course this can be re-researched as the JG book team is currently in revision mode, but I have a tendency to believe what's in print as Terry McManmon was the former NTL, he has a very original '70 LT1 and he's a meticulous fella when it comes to dotting the 'i' and crossing the 't' details.

If the JG is correct and the AIM isn't, I think I can conjure an explanation. Remember, Corvette was unique in 1970 as the car's production debut was delayed to 1/1/70 while St. Louis continued churning out '69 MY cars. Since the '889 and '890 relays freely interchange with one another, it may well have been a case of excess '890 inventory on-hand when the '70 production build actually started.

That combined with a 'short' MY build out could explain why we see 1969 horn relays on '70 Corvettes vs. the '71 version ('889) that's called for by the AIM....

[David L.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

It's interesting that both the 1970 Corvette and 1970 Camaro show GM # 1115889 as horn relay in the assembly manuals. I do not have any Corvette judging guides as I prefer to do my own research (32 years so far). I respect the work put into these judging guides but they are only guides based on research by others. Since these judging guides seem to be revised periodically I assume errors are found in them. I have also found errors in Chevrolet parts catalogs as well as assembly manuals although very few. As far as I am concerned the 1970 horn relay case is still open and may always be open for the rest of time.

By the way, the 1970 Corvette was not unique in 1970. The 1970 Camaro did not make its debut until late Feb. 1970 because of production problems with the rear quarter panels.

[Chuck S.]

Re: 1969-1971 Horn Relays 1115890 & 1115889

For right or wrong, Chuck, the current JG book defines the horn relay that's correct for 1970 as being the '890 and not the '889...

That's correct according to your description of the part numbers, but the relays are not identified by part number, only by description (sketch). I wasn't saying what was right or wrong...my intent was to provide help to Dave with what the AIM says.

I would have to dig out my relay to confirm that it does match the description in the TIM&JG, but I seem to recall that it had a metal mounting tab as described. If I had found the later plastic tab, I would have been disappointed. My opinion is the later relay config was strictly to reduce cost...the plastic mounting tab would be less desireable from the durability perspective. My car build date is G30...if it has the metal tab relay, it's a reasonable assumption to believe all 70 production had this relay (890?).

This wouldn't be the first time that the AIM, or TIM&JG for that matter, had erroneous info on minor details, but like you, I have great faith in the accuracy of TM's observations and documentation as TL.