Hey guys,

I am trying to diagnose a starting problem on my old 93 max that I gave my parents. there was problems starting and the battery/alternator were fine. The starter didnt grind.. so eventually we found a small black bosch relay with 5 wires on the drivers side of the engine bay between the battery and the firewall.

My dad cut it out because it looked like it had corrosion and one of the pins was fried.

He bought a new one with a new wiring harness, but didnt keep the old one so I could match the wires up. The was a red, yellow, blue and 2 black.

The red is a constant 12 volts, blue was grounded to the chassis, yellow wasnt a 12v when in the acc position (no voltage ever) and I couldnt trace the 2 black wires.

Is this a relay related to starting/ignition? The 2 black wires are too small to carry a load to the started, but maybe the go to another relay?

Is this some sort of relay associated with the alarm?

I havent found anything in the search or google that was a help at all.

I appreciate any and all help.

Happy new year

 

Could you be more specific? Between the battery and firewall isn't very specific (virtually everything is in between the battery and firewall).. was it in between the battery and strut tower? In between the strut tower and firewall?

Was it in one of the clusters of other relays on the side near the fender? Or was it by itself? Out in the open?

It sounds like you kind of found a random relay out in the open by itself (of course can't say for sure without more detailed location info). If so, that isn't a stock relay. All the stock relays are clustered together in the little shells on the sides of the engine bay or right on the battery. It could be some left over relay for a previous aftermarket alarm or something.

Also, you said there were problems starting but you didn't state what the symptoms were. Did/does it take forever to start? Does it not start at all? Does it crank over but not start? Does it not crank?

 

Definitely isn't a stock relay. There is only 1 small black relay used in these cars, the interrupt relay (which actually is part of the starting circuit). But it's not at all what you're describing. It's located right above the SMJ next to the circuit breaker under the dash, not in the engine bay. And the wire colors are completely different. You're right, it probably is/was part of the aftermarket alarm.

Check the white and red wire at the starter for voltage when the ignition is in the start position (cranking). If it checks out, your starting system is fine and the starter should be spinning, assuming has a clean connection to the battery and ground of course. If there's no W/R voltage when cranking, try swapping the inhibitor relay in the relay box next to the battery.

 

Sounds to me like an alarm relay.

 

Thanks for the replies, I was trying to get my mom to take a picture and email it to me so I can post it, but so far that hasnt worked.

It was a separate relay loose in the engine bay, with a red(12V DC), yellow, blue (grounded) and 2 black wires connected to it. The yellow didnt do what I thought it should(12 volts when in acc position) and I couldnt trace the 2 black wires either. An alarm relay might make sense but there was no aftermarket alarm, just the stock one.

The symptoms of the starting issure were that it wouldnt crank, and they would boost it and it would sometimes start, but the battery was fine at 13.5 volts. sometime the car would crank, and sometimes it would start fine. I dont think the starter went bad yet, and the alternator and battery are fine so it led me to thinking it was a relay issue or maybe some frayed wiring somewhere.

 

In my 94 manual, the power to energize the starter solenoid comes from the ignition switch on a white/blue stripe wire to the starter relay that Nissan calls the inhibitor relay.

When the inhibitor relay energizes, it sends to power to the starter solenoid on a white/red stripe wire.

The coil inside the inhibitor relay gets power on a light green/red stripe wire and goes to ground on a black wire.

The light green/red stripe wire that energizes the inhibitor relay comes from another relay called the interrupt relay that is part of the stock security system.

The 94 Max does not have a relay located along the driver side fender between the battery and the firewall. The inhibitor relay is in the box in front of the battery and behind the headlight. The interupt relay is inside the car, up under the dash on the firewall behind the fuse panel.

I hope this can somehow be useful to you.

 

Voltage is not what starts the car. A starter draws amperage which is why when you go buy batteries they tell you the amperage the batteries they have to offer have. Load test the battery to see its amperage.

 

you cant have a current drawn by the starter if you dont have a voltage present...

thanks for the info guys... hopefully I cant get the car started next time i go see my parents.

happy new year!

 

Voltage is the speed of the electrons flowing through a conductor (wire) and Amperage is the amount of electrons flowing through the conductor. Much like water flowing through a hose.
Work backwards from the starter.

 

Voltage is the PRESSURE pushing the electrons through the conductor, similiar to psi in a water pipe.

 

Force, Pressure, Speed...same ****.

 

Alright Dennis, lets test your claim. You've got a long section of pipe with water flowing from left to right. Which side is positive and which side is negative?

 

If we attemp to apply the analogy of electricity, where electrons flow from negative to positive, to water flowing in the pipe, then the left end of the pipe is negative and the right end is positive.

 

Ok, then you know about electron flow. But because electrons move from negative to positive, i'm surprised you would make the water pressure comparison, high (+) to low (-) when the reverse is true for electricity (or at least how it ended up, if the poles were switched, it would make more sense). Anyhow IMO, "pressure" is just a bad description of voltage. It's best just to say what it is.. speed or velocity, in order to avoid the discrepancies you get when comparing electricity to water flow.

 

Ok, live and learn. If voltage is speed, that helps explain why the high voltage cross country power lines use 22,000 volts instead of 110. It gets the electricity there faster.

 

Using the water/pipe analogy force and pressure looks like speed, just like a bolt of lightening arcing across the sky.

 

How did this discussion start? Oh yeah, elusivemax came out of nowhere stating that voltage doesn't start cars, I think he was talking to me since I said to check for voltage from the relay to the starter coil. Funny stuff.

 

I'll prove you on watts law another day hectic. When i have time to spend on proving how it works as now it's late and tomorrow i have a long day at work. 'Tard.

 

Oh big man, calling people names.. There's nothing to "prove" me I learned how to calculate watts 16 years ago as a freshmen in HS buddy boy. You simply don't understand why I said to check for voltage. I wasn't telling him to measure current, I was giving him a procedure to check that the starting circuit is working properly. If there's no signal from that relay when the ignition is in the start position, there is a fault between the ignition switch and the relay, and the starter isn't going to operate. Regardless of whether or not the starter is connected to a fully charged battery.