Confused? Of course you are or you wouldn’t have found this page.

The Haynes manuals is extremely confusing regarding the labeling of the relays on Spitfires. The two ways they confuse readers is 1. the illustrations show right hand drive cars with different locations for relays, and 2. the naming of the relays is strange (at least to North American Spit owners).

There are three relays grouped together on the bulkhead next to the master cylinders (not the battery box as Haynes says…this is for Right Hand Drive cars in the UK). The relays are the Hazard Flasher relay, Horn relay, and another confusingly named relay:

Hazard Flasher Relay- top relay with two wires coming out;
purple (to the B terminal) and light green/pink (to the L terminal)

Horn Relay- the relay on the left with multiple purple wires coming out;
purple/yellow (to the C1 terminal), purple (to the C2 terminal) and purple/black (to the W1 terminal)

Overdrive Relay (D-type overdrives only)- multiple wires coming out;
brown (to the C1 terminal), yellow/purple (to the C2 terminal), white (to the W1 terminal) and yellow/green (to the W2 terminal)

“Other” Relay- the relay on the right with multiple colored wires coming out;
green/white (to the C1 terminal), black/purple (to the C4 terminal), white/orange (to the W1 terminal), Double black combo (black/blue & black to W2 with a black jumper between C2 and W2)

This relay should be called “Pre-Driving Checks” relay. The Haynes manual shows it in the photo calling it the Overdrive relay. When researching this page I found it also called Bulb Check relay and Starter relay. Apparently its job is to have a hand in the control such US government mandated devises as the seatbelt warning light/buzzer, EGR service light, and the PDWA (brake failure) light.

Blinker/Hazard Relays- (inside the car behind dash) two wires coming out;
light green/gray (to the B terminal) and light green/brown (to the L terminal)
This relay is exactly the same as the Hazard relay (under bonnet) and is located on the backside of the dash just under the tachometer on US cars.
Note that the Hazard and Blinker relays were combined into a single one for 1978-80 cars and was located behind the dash (somewhere below the tach or speedo). This “Flasher” relay now had 3 wires (light green/gray, light green/brown and green/light green).

Click here to visit the blinker/flasher troubleshooting page.

If you haven’t guessed, the Haynes manual’s wiring diagram is VERY wrong around this relay on 76 cars. A great wiring diagram is available for download however. (1.1Mb)

A 75 Spit, download this link. (1.1Mb)
A 78-80 Spit, download this link. (1.1Mb)
Here is a MkIV wiring diagram from the factory manual.