Fan Speed 4

[JRNY13]

Was driving today with AC on MAX and fan speed on 4 (I seldom have the fan speed on 4). After a few minutes of driving I could hear a fairly loud "pop" from the relay compartment and the blower motor just died. It seemed to only work on speeds 1 and 2. After a few seconds of playing around with the mode selector knob and and fan speed switch everything went back to normal and speed 4 worked again. After a few minutes, the same thing happened. Do I simply need to replace relays numbers 23 and 24 from the schematic? Would I replace them with the Bosch changeover relays listed on DMC's website?

[Chris4099]

It's actually the circuit breaker. Running at speed 4 caused it to overheat and trip, which shuts down the fan. Speeds 1 and 2 are fused and don't use it, so they were still able to function. Once it cooled and reset, speeds 3 and 4 start working again. To fix, you'll want to replace the 25 amp circuit breaker in the relay compartment. I went with a 30 amp to avoid issues like that going forward.

Is your relay compartment original? If so, you should really just replace everything with an upgrade kit. If the relays have a metal case on them that have corrosion, then chances are they are original. Upgrade kits from any of the vendors should come with new circuit breakers too. The other breaker next to the blower motor one runs the radiator cooling fans which you definitely don't want going out!

[Chris 16409]

Just to note, some of the early Bosch "changeover" relays had a metal case and are marked "Bosch". The OEM relays had a metal case but no brand identification. The new "Bosch" style relays have plastic cases. DMC sells ones with the purple cases. Bosch no longer manufactures the relays. Tyco took over production from Bosch. If you don't mind going "second hand," late model Saab cars used Bosch relays. They are all over the place at wrecking yards.

[JRNY13]

It's actually the circuit breaker. Running at speed 4 caused it to overheat and trip, which shuts down the fan. Speeds 1 and 2 are fused and don't use it, so they were still able to function. Once it cooled and reset, speeds 3 and 4 start working again. To fix, you'll want to replace the 25 amp circuit breaker in the relay compartment. I went with a 30 amp to avoid issues like that going forward.

Is your relay compartment original? If so, you should really just replace everything with an upgrade kit. If the relays have a metal case on them that have corrosion, then chances are they are original. Upgrade kits from any of the vendors should come with new circuit breakers too. The other breaker next to the blower motor one runs the radiator cooling fans which you definitely don't want going out!

Thanks. That would have been my second guess. Wow, it doesn't take much time for it to overheat in there. DMC's store lists 40amp circuit breakers. I assume this is the proper upgrade?

[Chris4099]

Nope, the 40 amp is for the cooling fans. 25 amp is stock value for the blower and will work. But if you get one on your own (they are standard automotive breakers) then I prefer 30 amp as it will give you a little more buffer if you like to keep it on speed 4 for long periods of time.

Also, I forgot to mention, the stock setup uses spade connectors. These don't handle the high current well. New breakers come with ring terminals. You cut off the spade connectors and put on the ring terminals. This can help reduce false tripping as well.

[Bitsyncmaster]

I seem to remember testing my blower motor current on fan speed #4 and it was around 24 amps. So you defiantly want to upgrade the 25 amp breaker to a 30 amp. I think that was a recall update.

[JRNY13]

I seem to remember testing my blower motor current on fan speed #4 and it was around 24 amps. So you defiantly want to upgrade the 25 amp breaker to a 30 amp. I think that was a recall update.

Visually, is there any way to tell the amp rating of the circuit breaker I have now?

[Bitsyncmaster]

Visually, is there any way to tell the amp rating of the circuit breaker I have now?

It should be marked on the top. Just pull it out of the holder to look at it.

[mluder]

I can corroborate. Toby at DMC NW confirmed the stock breaker is undersized for the draw on the fan motor speeds 3 and 4 and sold me a uprated breaker to replace the stock 25 amp. Don't remember what amperage it was but it was plug and play - meaning still had spade connectors. Only cost me a couple of bucks.

Cheers
Steven

[David T]

I can corroborate. Toby at DMC NW confirmed the stock breaker is undersized for the draw on the fan motor speeds 3 and 4 and sold me a uprated breaker to replace the stock 25 amp. Don't remember what amperage it was but it was plug and play - meaning still had spade connectors. Only cost me a couple of bucks.

Cheers
Steven

Most of the Delorean venders sell what they call a "Relay Update Kit". Each vender has a slightly different kit but it consists mainly of a cooling fan circuit breaker, a heater fan circuit breaker, and a fan fail relay bypass. Some add some relays which are higher capacity. Make sure every fuse is the correct size for it's location. Leave the cover off for the fuseblock. DMCH has a pretty label for all of the relays, fuses, and circuit breakers. Make sure there is nothing plugged into the hot start plug. Add a 10 AMP in-line fuse to the big red wire going to the door lock module. While you are in there look for any signs of overheating, any wires that are discolored, crisp, melted plastic, etc. The other big problem is wire connectors that "back-out" when you push a relay or fuse into the connector block. If that happens the connector doesn't grip the tab, it only touches it on the tip making a bad connection.

[JRNY13]

Just so I'm clear--the fan speed 3/4 circuit breaker is the one with the 4 wires connected to it?

[Bitsyncmaster]

Just so I'm clear--the fan speed 3/4 circuit breaker is the one with the 4 wires connected to it?

Correct. That is the normal stock wiring with the starter relay update.

[GS450-Junkie]

In regards to the 2 circuit breakers....#19, #20.

Does it matter which wires go to the BATT & AUX post? For #19 (cooling fans) I have a 40 AMP breaker with BROWN/ORANGE to BATT, BLACK/ORANGE to AUX.

For #20 (blower fan) I have a 30 AMP breaker and I'm not sure how to hook it up. I see 4 BROWN wires, 1 is smaller and goes to the relay, 3 are larger and go into the main wiring harness for the car. What goes where?

After doing a fuse box overhaul, and all brand new relays and circuit breakers I have no interior fans blowing anything at me. Trying to double check my work. :headscratch:

[Bitsyncmaster]

In regards to the 2 circuit breakers....#19, #20.

Does it matter which wires go to the BATT & AUX post? For #19 (cooling fans) I have a 40 AMP breaker with BROWN/ORANGE to BATT, BLACK/ORANGE to AUX.

For #20 (blower fan) I have a 30 AMP breaker and I'm not sure how to hook it up. I see 4 BROWN wires, 1 is smaller and goes to the relay, 3 are larger and go into the main wiring harness for the car. What goes where?

After doing a fuse box overhaul, and all brand new relays and circuit breakers I have no interior fans blowing anything at me. Trying to double check my work. :headscratch:

I'm not sure if the BATT & AUX post really make a difference with the operation of the breaker. But you want the starter relay wire to attach to the post with the battery (always 12 volts) wire. You may need to meter the wires to find the battery wire since you have 4 brown wires.

[David T]

It does make a difference. You should try to always put the power onto the BAT connection and the load onto the AUX terminal.

[GS450-Junkie]

It does make a difference. You should try to always put the power onto the BAT connection and the load onto the AUX terminal.

Here's my confusion...
I have 4 Brown wires on my 30 AMP breaker. 3 Lg Brown, 1 Small Brown. Only 1 LG Brown shows power when switched. 2 need to go to Batt, 2 need to go to Aux. Which other wire goes on Batt?

The 40 AMP breaker has Brown/Orange and Black/Orange. The wiring schematic shows Battery power coming to Brown/Orange, yet when I check with a meter my power is coming to Black/Orange when switched.

The 25 AMP breaker has one tiny red wire that must run the antenna. It is hooked to Batt. I also have 1 Lg. Brown wire that hooks to this breaker at Batt. It disappears into the wiring harness. Now, I'm adding a DLM which my car was missing. The instructions say run the red power lead for the DLM to the Batt post on the breaker, but there is no more spots to hook it to.

[Bitsyncmaster]

Here's my confusion...
I have 4 Brown wires on my 30 AMP breaker. 3 Lg Brown, 1 Small Brown. Only 1 LG Brown shows power when switched. 2 need to go to Batt, 2 need to go to Aux. Which other wire goes on Batt?

The 40 AMP breaker has Brown/Orange and Black/Orange. The wiring schematic shows Battery power coming to Brown/Orange, yet when I check with a meter my power is coming to Black/Orange when switched.

The 25 AMP breaker has one tiny red wire that must run the antenna. It is hooked to Batt. I also have 1 Lg. Brown wire that hooks to this breaker at Batt. It disappears into the wiring harness. Now, I'm adding a DLM which my car was missing. The instructions say run the red power lead for the DLM to the Batt post on the breaker, but there is no more spots to hook it to.

Normally brown wires are always battery power (hot always). Schematic shows two brown wires one for fan #3 and one for Fan #4 are brown wires attached to the load side of the breaker. I think the starter modification was a brown wire which should go to the battery side of the breaker. Of course the brown feed wire would go to the battery side of the breaker.

[DMC5180]

Here's my confusion...
I have 4 Brown wires on my 30 AMP breaker. 3 Lg Brown, 1 Small Brown. Only 1 LG Brown shows power when switched. 2 need to go to Batt, 2 need to go to Aux. Which other wire goes on Batt?

The 40 AMP breaker has Brown/Orange and Black/Orange. The wiring schematic shows Battery power coming to Brown/Orange, yet when I check with a meter my power is coming to Black/Orange when switched.

The 25 AMP breaker has one tiny red wire that must run the antenna. It is hooked to Batt. I also have 1 Lg. Brown wire that hooks to this breaker at Batt. It disappears into the wiring harness. Now, I'm adding a DLM which my car was missing. The instructions say run the red power lead for the DLM to the Batt post on the breaker, but there is no more spots to hook it to.


Blower Fan Breaker (25 Amp) the switched Lg Brown wire and Small brown wire to breaker [BATT] The other 2 LG brown wires to [AUX]

Cool FAN Breaker (40 amp) Black/Orange is the the Feed from the FAN relay (30) to Breaker [BATT] Brown/orange From Breaker [AUX] goes to blue Fan fail socket (87)

NOTE: My car had Brown/Orange on both sides of the Cool fan breaker. Some Main wire harness have the BLACK/orange wires Like yours (must have been an undocumented production change)

The Small Red Antenna power wire goes [AUX] the DLM breaker mounted behind the DLM it should be paired with the other Red wire.