Are all relays created equal?

My research has told me there are various part numbers for the various relays (S2 2+2). It has also told me that all 6RA relays do all jobs (horn, fan, rear window).

Thoughts/advice please?
Pat

6RA is a Family of relays. The Lucas Part Number (e.g. 33209 for the Horn, 33232 for the Fan) determines the characteristics specific to the function. They differ in the number of contacts, Normally-Open vs Normally-Closed, current rating of the contacts, and other factors. Some of them, e.g. that for the Heated Rear Window incorporates very specific functionality (a resistor that comes into the circuit in one position, to dim the warning light at night). Unfortunately, the “usual” vendors don’t tend to offer all the variants today, and substitute one intended for a different function. They can be made to work, but sometimes require a little work.

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I’m not sure how Lucas part numbers correlate to Jag part numbers, but I can tell you that SNG Barratt shows an E-type horn relay as C17338 which is incorrect, the correct part number for the horn relay is SRB111 which is also available through SNG but you need to search on that part number. C17338 is a 3 connector relay, SRB111 has 5 connectors.

If you are referring to the Series 2 Horn Relay, then I do not quite agree with you, though I do think that SNG Barratt may have things wrong. The Jaguar Parts List indicates that the relay has Jaguar Part Number C17338 - that number is correct. In the day, this translated into a Lucas 6RA family relay with Lucas part number 33209. As I understand it, this relay had 4 terminals W1, W2, C1, C2 though there were two tangs on the C1 terminal, so it may be considered to have 5 terminals. The relay that SNG shows under part number C17338 has 3 terminals C1, C2, and W1, with W2 being wired internally to C2. This will work fine provided it is wired accordingly - i.e. the horn switch is wired to W1, +12V is wired to C2, and the horn is wired to C1. The SNG web site does state that if you require a 4 terminal relay for this application, you should use the Lucas Part SRB111 relay, which appears to match the original terminal configuration of the Lucas 33209. Interestingly, if you look at the Fan Relay for the S2, the Jaguar Parts List indicates Jaguar Part number C18122, which translates to Lucas 6RA Family Relay part number 33232. This IS a 3-terminal relay with W2 connected internally to C2. If you look on the SNG Barratt web site, it proposes an SRB111 for Fan Relay C18122, which will require some rewiring - a cable link from W2 to C2. I’m therefore wondering whether the error on the SNG web site may be that it should be proposing the 3-terminal relay for Jaguar 18122 (the Fan Relay), and not for Jaguar 17338 (the Horn Relay). It’s also worth noting that another characteristic that differentiates models of relay is whether they are intended for intermittent use (like the horn relay) or continuous use (like the fan relay). As I mentioned in my earlier post, there used to be specific models of relay from Lucas for each application. As these models have ceased to be available, vendors have substituted a smaller number of more generic relays, with the result that a little rewiring may be required, or worse…